ALBERT

Description: It has been shown that dried sugar-beet pulp contains a high percentage of pectose. A number of successive digestions of 1 hour each with 0·5 per cent. ammonium oxalate at 100° C. extracts an amount of pectin equal to 34·5 per cent. of the weight of dried beet pulp, basing the determination on the weight of crude pectin precipitated when the extracts are run into 95 per cent. alcohol. A single prolonged digestion gives a yield of crude pectin equal to 32·2 per cent. of the dried beet pulp.Digestion with acidic reagents, such as 0·5 per cent. oxalic acid, 0·6 per cent. tartaric acid, N/20 hydrochloric acid, etc., leads to a quicker extraction of pectin, owing to a speeding up of the pectose to pectin hydrolysis. The yield of pectin, however, is not thereby necessarily enhanced, since under such conditions the pectin undergoes a slow secondary hydrolysis during the extraction with the formation of reducing substances not precipitated by alcohol.Prolonged digestion at 100· C. of dried sugar-beet pulp with water alone also leads to a satisfactory extraction of pectin.

Description: 1. The relative proportions of exchangeable bases in nine soils from the east of Scotland area and the changes effected by dilute chloride solutions have been examined.2. The changes due to N/50 solutions are large, and magnesium is displaced to a greater extent by calcium than by potassium.3. The changes due to N/500 solutions are very small, comparable to what might be expected in manurial practice, and not greater than field sampling error.4. The content of exchangeable bases and their relative proportions, therefore, seem to be fairly permanent for any soil under normal conditions, but vary considerably from soil to soil, and should prove useful as an additional characteristic of soil type as distinguished in the field.

Description: (1) The desiderata of a sampling-method are outlined, and the particular case of sampling a large number of potato plots discussed.(2) An analysis is made of the yields of 54 sub-plots of the Rothamsted Potato Experiment of 1928, both as estimated by a sampling-method and as determined by large-scale lifting.(3) It is shown that most of the significant results of the experiment are obtained from the sample-yields, but that the higher standard error per plot obscures the effect of superphosphate.(4) It is concluded that at Rothamsted 102, and at Woburn 56, plants would have to be lifted to give a sampling-error as small as 4 per cent. It would then be profitable only to sample experimental plots of 1/20th acre or more in area.Finally it is a pleasure to record our indebtedness to Dr R. A. Fisher for much valuable advice and criticism: and to Mr H. J. G. Hines for assistance with the field work.

Description: The last issue of this Journal (p. 132) contains a paper by Dr R. A. Fisher on the effect of Silica upon the growth of Barley at Rothamsted, which begins by stating that his data “show conclusively that the view previously rejected that the silicate acts by making available to the plant the actual reserves of soil phosphates must be regarded as strongly established.” Twice elsewhere Dr Fisher states that this erroneous conclusion of previous investigators is due to the fact that they had considered only the proportion of phosphoric acid in the ash and had overlooked the increase in the total phosphoric acid in the crop. As Mr Morison and I were the previous investigators in question I turned to our twenty-three-year-old paper with some curiosity to ascertain the grounds for this magisterial dismissal of our conclusions, for my remembrance of the subject did not tally with the opinion Dr Fisher attributes to us. Still less do I agree now that I have re-examined our original paper.

Description: In a former number of this Journal (1), there appeared a report on the mechanical analysis of soils by this sub-committee of the Agricultural Education Association. The report contained proposals for certain modifications of the earlier A.E.A. (1906) method, of which the most important were the introduction of hydrogen peroxide as a dispersive agent in the preliminary treatment, the use of the pipette method for the actual mechanical analysis, and the abolition of the fine gravel (3 mm.–1 mm.) fraction. This report was officially adopted by the A.E.A. and the method of mechanical analysis therein proposed was accepted as the new standard to replace the 1906 method. The full details were published in the Journal of the Association (2).

Description: The study has comprised a detailed analysis of twelve samples of soil, ten of which were samples of typical peat soils, the other two being samples of normal soils. The degree of humification of the organic matter of the samples varied, that in the wet peats being high and low in the dry peats.Extracts of the soil were obtained by the use of boiling hydrogen peroxide, 20 per cent, hydrochloric acid and 2·5 per cent, caustic potash.Hydrogen peroxide extracted roughly 70–80 per cent, of the soil nitrogen, 60–70 per cent, of this soluble nitrogen appearing as ammonia through the oxidising effects of the reagent. The nitrogen compounds of wet peats were more easily oxidisable to ammonia.

Description: 1. The capillary pull of an ideal soil has been determined by measuring the maximum hydrostatic pressure (H) sustainable by a liquid surface formed, amongst an assemblage of uniform spheres of mean diameter 0·0374 cm. (2a). It has been found that using liquids of low surface tension like benzene to avoid contamination, the constant K in the equation Hgp = KT/2a has the weighted value 9·5.2. Values of K for single apertures between three and four spheres in contact have been determined, using steel spheres of a diameter ⅛ in. and benzene. It is found that K does not vary rapidly for four spheres and has a value between 9 and 10 for apertures in which the ratio of breadth to length varies between 1·0 and 0·4.3. The equivalent capillary tube is the circular or elliptic cylinder touching the spheres forming the aperture. This assumption gives values of K in fair agreement with observation.4. The value of K is practically independent of variations of pore-space ranging from 36 per cent, to 40 per cent, such as usually occur in ordinary packing.

Description: A new and improved type of dynamometer is described which by a simple interchange of parts can be used with the same percentage accuracy for all types of work from the lightest to the heaviest.The instrument consists of (a) an hydraulic link weighing 16 1b. and placed in the hitch, (b) a recording mechanism weighing 15 lb. carried on any convenient part of the implement, and (c) a control box weighing 4 lb. carried by the operator. When packed in a stout box for transit and with all accessories the total weight is less than 100 lb. The instrument is of robust construction and has a minimum number of moving parts. Adjustments for stylus pressure, etc., are provided, but the necessity for using them hardly ever arises.The instrument operates by recording the amount of movement in a Bourdon tube filled with oil and connected by narrow bore copper tubing to the oil in the hydraulic link.

Description: 1. The formation of colloidal CaHPO4 by the interaction of CaCl2 and Na2HPO4 in the presence of neutral casemates has been demonstrated.2. The colloidal CaHPO4 is shown to be non-diffusible across a membrane of cellophane.3. A theory is outlined which will account for the secretion of the high concentrations of calcium and phosphorus in milk from the low concentrations of these elements in the blood.

Description: An unknown phosphorus fraction previously recorded by the authors as frequently present in calf blood, is shown to be nucleoprotein and due to the presence of precursors of fully mature erythrocytes. The same fraction may also appear in small amounts in human blood and in horse blood, and always occurs in very large amount in the nucleated erythrocytes of birds.

Description: In the account of “Pining” in sheep given by McGowan(1) there are so many points of similarity, both in the symptoms and in the general environmental conditions under which the disease is developed, with the disease known in New Zealand as “Bush-sickness,” as to suggest that these two diseases may be of a similar nature.

Description: On the arid, sparse, phosphorus deficient pasture of the Vryburg district of the Cape Province, grading up of scrub cattle, by combining the introduction of pure bred bulls with the feeding of bone meal to the cows, is attended with great success so far as shown by the first crossing. Remarkable differences in favour of the mineral supplement are shown, in respect to reduced mortality incidence, increased fertility of cows, and superior development of calves.

Description: The mechanism by which viscogen (calcium saccharate) brings about an increase in the viscosities of milk and cream has been investigated.The primary reaction appears to be the formation of a precipitate of insoluble (tri-calcium) phosphate. Considerable quantities of casein are carried down by the precipitate, and this co-precipitation of casein is probably the single factor which most influences the viscosity.Casein is not directly precipitated by viscogen, but the viscosity of its solutions is slightly increased as a result of their higher alkalinity due to this reagent. This action of viscogen is relatively unimportant in influencing the viscosity of milk or cream.

Description: 1. The value of the knowledge of the saturation capacity of a soil as an aid in its characterisation and classification is briefly stated.2. A short account is given of the more important methods in use for determination of saturation capacity.3. The theory underlying the method of Page and Williams, and the possible defects of the method are discussed.4. The results of an investigation of this method lead to the following conclusions:(a) Leaching the mixture of soil and calcium carbonate to 2 litres is in sufficient to displace from the soil all its exchangeable bases.(b) In view of this, it is recommended that 3 litres or more of filtrate be obtained, or preferably, the amount of soil employed be reduced to 10 grm.(c) The leaching solution remains in contact with the soil mixture for a period adequate for the normal sodium chloride solution to be saturated with calcium carbonate.(d) The difference in the amount of calcium, derived by solution from the carbonate, in the first and second litres of filtrate, is sufficiently small to be neglected.(e) The tardiness with which the reaction proceeds to completion is probably due to the difficulty experienced in displacing the final amounts of adsorbed ions, rather than to the presence of calcium ions in the leaching solution.(f) The incompleteness of the reaction renders the method of Hissink inaccurate for the calculation of the saturation capacity.(g) The variation in the character of the colloidal material of soils i s to some extent reflected in the value of the ratio of the calcium passing into solution through exchange reactions in the second litre, to that dissolved in this manner by the total volume of filtrate.

Description: 1. Considerable differences were found in the specific conductivities of different soils at any one time of the year, and considerable differences in any one soil at different times of the year, the specific conductivities being highest in March and lowest in June and July. Hence it is only possible to compare different soils when samples of these soils are taken at the same time of the year.2. A relation has been found between the specific conductivities of the soil extracts and the mean weights of lint per plant per row in the case of 2 strains of Ishan cotton. Other data are presented showing that the specific conductivity of a 1 to 5 soil extract is an index of the fertility of the soil.3. It has been found that the specific conductivity of a soil decreases under continuous cultivation. There is evidence that the rate of solution also decreases under the same condition.

Description: Herd statistics of cattle in India suggest that for animals of about 3500 lb. yield capacity a calving interval of rather less than a year will give the best results in the following lactation. For cattle whose yield capacity is 6000 lb. an interval of 420 days is desirable while one of less than 335 days is seriously injurious.Study of individual cows and their recorded histories reinforces the above conclusions and also suggests that the interval should be longer in early lactations than in late and progressively longer as the milking capacity increases.It also indicates that unrestricted access to the bull may prevent the real yield capacity of a cow being discovered.

Description: 1. In pot experiments with Glycine hispida and Vicia faba L., fresh chaff incorporated with the soil caused a significant increase in the number of nodules produced on inoculated plants, this increase being augmented by the further addition of phosphates.2. Fresh chaff, added at the time of sowing and inoculation, had more effect than chaff which was allowed to decompose in the soil for a month.3. Fresh chaff increases the multiplication of the nodule organism in sterilised soil.4. In soy beans without nodules, the chaff depressed the growth of the tops, but this depression did not occur either with soy or broad beans where nodules were present.5. In a field experiment made at Rothamsted, chaff, freshly ploughed in, increased the growth of broad beans and also of wheat sown the next season on the same ground.

Description: In the first paper of this series (10)1, Keen and the present writer discussed work by earlier authors on the approximate specification of the nature of a soil by a single soil constant, in place of a detailed analysis, and described experimental work designed to show the significance of a number of simple physical measurements. The chief objects of the present paper are to describe the results obtained with such measurements as applied to a number of Natal soils, and to discuss the value of some other easily obtained physical data as a means of specifying the nature of a soil. Work of this type was discussed at the International Congress of Soil Science at Washington in 1927, and it was resolved that co-operative work on an international basis should be undertaken.

Description: 1. Cereal plots were sampled by three different methods; two systematic, and one involving a random location of sampling units.2. The disadvantages of the systematic methods as compared with random sampling, emerged clearly.3. These disadvantages were further emphasised in an analysis of earlier data on sampling methods. For this purpose the methods and. results of certain recent contributions to statistical theory were used.4. By the use of a random sampling method, the variance due to sampling errors may be made a satisfactorily small fraction of the total variance of cereal plots one-fortieth of an acre in area.

Description: 1. The nature of the replaceable base in a clay or soil exerts a profound effect on the physical properties. Clay-like properties are exhibited most strongly in the case of lithium, sodium, and magnesium.2. The proportion of fine material in a soil (i.e. that which remains in suspension in a column 10 cm. high after 14 days) cannot be correlated with other physical properties. Thus a soil of which over 50 per cent, was dispersed to this extent was the least plastic of those examined.3. A comparison of sodium, potassium, and calcium clays and soil showed that potassium resembles sodium in its chemical relationships as indicated by base exchange, but is very different from it in such physical properties as plasticity and permeability.4. Using mixtures of one-half normal chlorides of two bases, calcium and potassium are absorbed in equivalent amount while the sodium absorbed is only one-sixth of the amount of either of the other two.

Description: The cobaltinitrite method, in the volumetric form here described in detail, enables known amounts of potassium to be accounted for quantitatively, independently of the presence of alkaline earth sulphates, or phosphates, provided that the amount of potassium is not varied over too great a range. The factor 0·000830 gm. K2O per c.c. N/10 KMnO4 suits the procedure described over a range of about 3 to 50 mg. K2O. Outside this range, or for highly accurate work within it, it may be desirable to calibrate the method.The method may be applied, in plant-ash analyses, indifferently to the original extracts containing other bases and phosphates, or to the mixed sulphates weighed for sodium and potassium together. It is applicable to small-quantity work upon soils with greater exactness and speed than is the perchlorate method. Citric acid extracts can be handled, with a relatively short manipulation, to give satisfactory results.Some analyses of ammonium chloride extracts have been unsatisfactory, and attention is called to the desirability of setting exchangeable potassium determinations upon a firmer analytical basis, by investigation of methods of freeing the extracts from ammonium salts.

Description: 1. Digestibility trials with oats, carried out with White Leghorn cockerels, indicate that certain varieties of oats are more suitable as sources of food nutrients for poultry than others.2. In the trials carried out, Grey Winter oats proved more suitable than Black Bountiful or Scotch Potato oats for poultry feeding.3. The suitability of varieties of oats for poultry feeding appears to be linked with the fibre content, and thin husked varieties appear to be most suitable for this purpose.4. Oats do not appear to be very palatable to poultry.

Description: The results of four experiments are described in which twenty-five pigs were fed on a ration containing half a pint of milk. Eighteen were fed on control rations, generally considered to be adequate, and of which in one series dried separated milk was a constitutent.In every case the fresh milk produced an increase in live weight over the controls varying from 8 to 10 per cent. Less dry matter per lb. increase in live weight was consumed by the experimental pigs than by the controls.The returns for half a pint of milk fed per pig daily expressed as pounds live weight gain per gallon of milk fed, were as follows:The higher values in Exps. 2 and 4 may have been due to the fact that the pigs were individually fed but differed in that the milk was mixed with the food in Exp. 2 and fed separately in Exp. 4.

Description: The distribution of salts in the soil is generally related to compactness of the soil profile as judged by the distribution of gypsum, of calcium carbonate aggregates and of soil colour. The relation already established between salt content and fertility is now expressed as a relation between compactness of profile and fertility. The data agree well with geological views as to the origin of this soil. Influences of which the soil profile is the product are also discussed.I am much indebted to Mr G. W. Grabham for practical instruction in field work and for information as to the origin of Gezira soil. I wish also to thank Dr A. F. Joseph for his interest in this work and for facilities placed at my disposal.

Description: In regard to phosphorus partition, the same general relationship holds between the blood of lambs and of the mother ewes, as between the blood of calves and the mother cows. Total phosphorus is about twice as high in lamb blood as in maternal blood, inorganic phosphorus about twice as high, and organic acid-soluble phosphorus about three times as high. A considerable proportion of an acid-insoluble phosphorus fraction, probably nuclein, may be present in the red corpuscles of lamb blood and may even be present in foetal blood. The organic acid-soluble fraction is confined to the corpuscles, both in young blood and adult blood, but i n one case of a six-month calf foetus a small proportion was noted in plasma.

Description: Though it is neither customary nor perhaps desirable to utilise sugar beet for feeding purposes, it is conceivable that circumstances might arise occasionally when a farmer would be desirous of feeding the whole or part of his beet crop. This is indicated by the fact that enquiries as to the value of sugar beet for pigs are received from time to time. During the carrying out of the investigation into the value for pigs of dried sugar-beet pulp and molasses-sugar beet pulp, an account of which work is given in this issue of the Journal (1), the opportunity was taken of making a similar study of whole sugar beet. A dual investigation was made, consisting of a digestion trial under the conditions of the metabolism room and a large-scale feeding trial under ordinary farm conditions. It was hoped that the evidence from this twofold line of enquiry would not only settle the question of the value of sugar beet in the feeding of pigs, but also throw light on the subject of the value of root crops in general for swine.

Description: The severe climatic conditions under which cotton is grown in the Gezira make it desirable to establish relations between meteorological data and irrigation practice. By means of a rapid and fairly accurate balance it is practicable to measure water loss when small boxes containing moist soil are exposed for short periods and under different conditions. The scope of this method has been ascertained by preliminary experiments as to (1) the dependence of water loss on moisture content of the soil, (2) the distribution of water loss through the day, (3) the comparison of water loss from sand and from. Gezira soil, and (4) the comparison of water loss from shaded and unshaded soil. The application of data so obtained to field problems is facilitated by the fact that in respect to distribution and amount losses from soil are related to loss shown by a Piché evaporimeter. Within the canalised area alternation of irrigated and fallow land is responsible for local variations in atmospheric conditions. A daily fluctuation in the moisture content of surface soil from fallow land is recorded and may be instrumental in favourably modifying its physical properties. The heat of wetting of Gezira soil has been measured.

Description: (1) The mineralogical composition of the fine sand fraction of certain soils from the south-east of Scotland is described.(2) The soils are shown to possess a fairly high content of silicate minerals in a comparatively fresh state.(3) The distribution and amount of potash, phosphate and lime-bearing minerals in the soils is discussed.(4) The soils can be grouped according to their mineral content and this grouping is found to depend on the geology of the parent material.(5) All the soils are formed on glacial drift and the results suggest that the local rocks have a preponderating influence on the composition of the matrix of the drift.

Description: (1) In absence of decomposing organic matter addition of nitrate led to no loss of nitrogen.(2) On addition of small quantities of fermentable matter such as glucose there was (a) rapid depletion of nitrates and oxygen, but no denitrification, and (b) increase in acidity, carbon dioxide and bacteria. The greater part of the soluble nitrogen was assimilated by microorganisms or otherwise converted and the greater part of the added carbohydrate was transformed into lactic, acetic and butyric acids.(3) The organic acids were formed from a variety of carbohydrates. Lactic acid was the first to be observed and appeared to be formed mainly by direct splitting of the sugar. It decomposed readily, forming acetic and butyric acids. Some acetic acid was formed by direct oxidation of lactic acid, with pyruvic acid as the intermediate product. All the acids were, on standing, converted into other forms by micro-organisms.

Description: (1) Soil surveys are classified into (i) preliminary reconnaissance surveys, (ii) broad ecological surveys, (iii) detailed physiological-ecological surveys, and (iv) special-purposes surveys. The objects of each are briefly discussed.(2) Particular consideration is given to the methods of physiological ecology, which attempt to assess the chief soil factors controlling plant growth.(3) Soil factors are grouped into (A) static factors, which do not fluctuate appreciably during a growing season, and (B) dynamic factors that may exhibit marked fluctuations within a season, or during years when climatic conditions vary.

Description: The conclusions of the 1927 experiments in spacing have been tested in greater detail in 1928 and are confirmed.From the 64-plot scheme containing a series of spacings in quadruplicate the following points emerged:(1) Variation of the width between the rows influenced the yields of sugar beet roots, the expectation of highest yield being on the narrowest spacings. There was a significant increase in yield to be gained by using 15” or 18” spacing instead of 21” or 24”. On the other hand width between the rows did not seem to influence the yield of tops and crowns.(2) Variation of the distance between plants in the rows up to 10” had no significant effect on the yield of roots. There was some evidence that above that figure a reduction in yield took place. It is interesting to note that in the case of the tops, spacing between the plants influenced the tonnage. There was a significant difference between the yields on the 4″ and 8″, and 4″ and 10″, but not between the 4″ and 6″, 6″ and 8″ or 8″ and 10″ spacings.

Description: The results of an investigation into the utilisation of sugar-beet pulp by ruminant animals were brought forward in a recent publication (I). It was demonstrated that sugar-beet pulp is highly digestible when consumed by ruminants. In respect of the digestibility of its N-free extractives and total organic matter, it compares very satisfactorily with maize meal. The process of drying the wet beet pulp in the factory does not depress its digestibility. Further, from the standpoint of digestibility, it is immaterial whether sugar-beet pulp is included in the rations of ruminants in the dry or the soaked condition. When, however, liberal allowances of the dried product are being fed to animals, it is desirable that the food should be well softened in water before feeding. This procedure ensures a higher availability of the digestible nutrients for productive purposes in the animal and also averts risk of choking trouble which sometimes arises, especially with sheep and lambs, during consumption of the dried beet pulp.

Description: Very considerable amounts of money are annually expended in Mauritius for the purchase of artificial fertilisers, and consequently it is of importance to know what happens to these substances when they are added to the soil. Extensive laboratory experiments have been carried out with nitrogenous fertilisers(1, 2), and also with phosphatic manures(3), and in order to complete the series an investigation into the availability of potash when applied in various forms was undertaken. Local practice favours the use of potash chiefly in the form of nitrate of potash and molasses, and on this account the availability of the potassium oxide in these two substances was tested, and in addition, in potassium sulphate.

Description: (1) A large series of data on the duration of gestation in the goat has been analysed and the constants calculated.(2) The frequency curve is unimodal and symmetrical, suggesting a single factor or a variety of factors acting simultaneously as the cause for birth.(3) Slight breed differences exist in the duration of gestation in the goat as in other species examined.(4) There is a continuous variation in the duration of gestation with the time of year at which conception occurs. Spring conceptions give shorter gestations than autumn conceptions.(5) There is a distinct difference in the duration of gestation for young and older dams. This is related to the age of the dams and not to the order of the births. Gestation is shorter in the young animal than in the older.(6) In the goat the size of litter has little or no effect on the duration of gestation.(7) Constants for duration of gestation in other species have been obtained. Variability increases with the duration of oestrus and about half the variability in any species with a long oestrous period may be ascribed to this cause.(8) The factors involved in fixing the duration of gestation in the species examined are evidently the same in all cases, and probably culminate in a single agency responsible for terminating gestation.

Description: In an earlier communication on this subject(1), the writers arrived at the conclusion that the main reason for the comparative failure of attempts to grow maize as a silage crop in this country was due in large measure to the general use of the late maturing variety, American Horse Tooth. It was predicted that success would probably depend on discovering a variety of maize which is able to reach the desirable stage of maturity under English conditions before being cut for the silo. Preliminary trials had indicated that the necessary qualities might be found in certain varieties like Saltzer's North Dakota, Longfellow, Compton's Early and White Cap, all of which mature at least a month before American Horse Tooth.

Description: In the course of investigations into the cause of an obscure pathological condition of the tea bush, it became necessary to make pH determinations of certain soils. Electrometric apparatus and a suitable centrifuge for clearing the solutions were not available. Considerable difficulty was experienced in making the determinations with accuracy by indicator methods owing to two causes. First, the turbidity of the soil solutions made comparison with standard buffer solutions somewhat difficult; secondly, the colours developed in the soil and buffer solutions with some indicators were different in hue, as distinct from shade or tint. This rendered exact matching quite impossible. The latter difficulties also arose when the drop ratio method was used instead of standard buffer solutions. The errors resulting from these causes were believed to be unduly large, and it was felt that greater accuracy would be attained if these difficulties could be overcome.

Description: 1. The interaction of physical conditions of the soil and the establishment of plant together with its subsequent growth and yield have been studied for wheat and swedes on a variable piece of land, maintained as a uniformity trial.2. Ploughing draught was taken as a criterion of the physical condition of the soil and various simple measurements on the crop were made from time to time during growth.3. The establishment of wheat showed substantial negative correlations with ploughing draught but the correlations between ploughing draught and the performance of the plant diminished as growth progressed. This was shown to be the result of the overwhelming importance of the spacing factor operating beneficially on plots where the plant was abnormally poor. The effect of this factor is traced step by step.4. Swedes differing from wheat in almost every detail of cultivation and growth, cycle showed no correlation between soil conditions and germination or between the various growth stages and physical soil conditions. The highest significant correlation was between the number of roots per plot after singling and ploughing draught and an explanation of this is given.5. There was a significant but only moderate correlation between the yields of the two crops.

Description: 1. A historical review of the dye adsorption method for the estimation of soil colloids is presented, and the method is criticised chiefly from the point of view of the isoelectric theory.2. A procedure for the detection of hydrous alumina in soils is described, involving the demonstration of the isoelectrio point of hydrous alumina by means of preferential dye adsorption in suspensions of various pH values.3. Satisfactory results were obtained with a mixture of acidic Biebrich Scarlet and basic Iodine Green. The former is adsorbed by hydrous alumina only on the acid side of its isoelectric point, and the latter only on the alkaline side.4. The characteristics of an ideal dye for use in studies such as those described are tabulated.5. The applicability of the mixture of dye-stuffs finally selected is demonstrated for a series of soils of varying basic ratio, and including examples of lateritic soils and clays.

Description: The question of the effect of iodine manuring on the iodine content of plants has recently assumed considerable importance in view of the use of iodine as a cure and preventive of simple goitre. Whether the theory that goitre is due to deficiency of iodine be correct or not, it appears to be well established that small doses of iodine act both as a cure and a preventive of enlargements of the thyroid. It has therefore been suggested that a simple and effective method of general prophylaxis, in areas where goitre is at present endemic, might be found in increasing the iodine content of foodstuffs such as milk and eggs, by administration of iodine, and of plants by iodine manuring.

Description: 1. The soil temperatures in Egypt at a number of depths have been recorded by means of continuous recording thermometers. In general, the records show that the amplitude of the temperature wave at the surface of the soil is considerably greater than the air temperature wave. There is, however, a considerable damping of the wave with depth, no daily variation in temperature being observed at a depth of 100 cm.2. No definite relation between the air and soil temperatures could be traced. The maximum air temperature was recorded in May and the maximum soil temperature in July.3. The amplitude of the temperature wave decreases with increase in depth. The decrease in amplitude of the soil temperature wave is not regular owing to variations in the physical properties of the soil layers. Between any two depths, the ratio of the amplitudes of the temperature waves is constant throughout the year. The amplitude of the soil temperature wave bears no relation to the amplitude of the air temperature wave.4. The time of maximum temperature at the soil surface is constant throughout the year at 1 p.m. The times of maximum temperature at depths below the surface lag behind the time of surface maximum, but they are constant throughout the year. When plotted against depth, the times of maximum at the various soil depths lie on a straight line.

Description: Since the soluble carbohydrates constitute a large proportion of most feeding stuffs and are in many the preponderating factor it is desirable that as much information as possible should be known about them, particularly with regard to their energy values in relation to feeding.

Description: 1. Examinations have been made of the losses involved by igniting fractions of tropical soils.2. It has been found that these losses are partly due to organic matter and partly to combined water; the greater part of the loss is due to water.3. In the clay fraction there is a correlation between the amount of combined water and the silica/alumina ratio; the greater the ratio the less the combined water. This is affected by the proportion of iron present.4. Lateritic soils lose more water on ignition than other soils but the lateritic material in soils is not necessarily evenly distributed throughout the fractions; those fractions containing the highest proportions of lateritic material lose the most water.

Description: The laboratory study of the physical properties of soil and clays can conveniently be divided into three stages:(a) Moisture content comparable to that under field conditions.(b) Thick pastes.(c) Weak suspensions.The use of the plastometer for experimental work on intermediate stage is described and recent developments of the theory of the flow for thick pastes under stress are outlined. It is shown that certain constants defining the material can be obtained from the experimental data. The two to which special attention is given are the pseudo-viscosity (a quantity analogous to the viscosity of true fluids) and the static rigidity (which represents the energy required just to cause the paste to flow and a measure of the solid cohesive properties of the system). The latter quantity is related to other physical measurements made under very different experimental conditions, e.g. the resistance of the soil to the passage of cultivation implements; the effect of chalk, etc., on the soil resistance; the moisture content at which a well-kneaded mass of soil is about to become sticky.

Description: Methods for extraction, concentration and determination of minute quantities of soluble carbohydrates, lactic acid and volatile fatty acids have been described. Different factors affecting the accuracy of the determinations have been studied and corrections, where necessary, have been suggested.

Description: An account is given of observations made during the first two years' treatment of grass according to the “New System of Grassland Management,” i.e. periodic dressings of nitrogenous manure followed by rotational grazing.The grazing provided by the nitrogen and no-nitrogen plots in the two years is given, measured in cow-day equivalents.A method of sampling the plots with a view to determining the total weight of herbage produced and its chemical and botanical composition is described.Botanical and chemical results obtained by this method are given and discussed.The percentage of clover on the nitrogen plots is about one-quarter of that on the control plots.The dry matter of the herbage on the nitrogen plots has, on the average, contained 17·7 per cent, crude protein: that on the no-nitrogen plots 15·5 per cent. The average age of the grass when sampled was 35 days.

Description: This paper is a record of the composition of the milk of an abnormal cow, during a period extending over three lactations. Although this cow was found eventually to be suffering from tuberculosis of the udder and lungs, no signs of the disease were apparent during the first two lactations recorded.The milk produced by this cow was abnormal during the whole period under review. Fat percentages were very variable, but the solids not fat content was consistently low, only 2 per cent. of the total number of samples analysed exceeding 8·5 per cent. in this constituent. Protein and lactose percentages were much below the averages for normal milk, but in the case of total ash the mean figures were normal. Of the ash constituents, the soluble portion was very high and the insoluble portion correspondingly low, the former presumably indicating a high chloride content. The percentages of phosphoric acid and lime were considerably below the mean figures for normal milk.Lactose and soluble ash percentages show a marked negative correlation, and moreover support the contention of Porcher and others that a definite lactose-chlorine ratio exists in milk.It is suggested that an abnormally low solids not fat content (i.e. low protein and lactose) and abnormal percentages of the individual ash constituents may be a sign of incipient disease affecting the organs involved in the secretion of milk.

Description: (1) The solubility of the potash in 34 soil samples from 13 soils typical of large areas in the East of Scotland has been determined by the methods of chemical analysis using (a) hot concentrated hydrochloric acid, and (b) 1 per cent, citric acid solution, and the values obtained compared with the quantities of potash existing in the exchangeable form. The total mineral potash has been determined for six samples and Neubauer's method of analysis has been applied to 10 samples and again compared with the exchangeable potash.(2) The average value of the total mineral potash in the soils examined was 2·04 per cent., which indicates the presence of comparatively large reserves of potash in these soils. No relation was found to exist between the total potash, and the quantities soluble in hot concentrated hydrochloric acid.(3) The average value of the HCl-soluble potash was 0·50 per cent, and in the profile samples there was generally an increase in solubility with increase in depth of soil.

Description: This series of investigations embraces studies of the more important factors, external and internal, which govern yield in field crops of cereals. It has so far dealt with the causes and influence on yield of fluctuations in density of plant population and also with certain inter-field differences of environment. Throughout, an analytical method has been employed, in which periodic observations have been made upon small samples distributed over a representative acre in a field crop. The best size of sample has proved to be a one-foot length of row, i.e. row of plants as seeded by the drill. The basis of this method—a “census” of an acre of corn—has been described and critically examined in an earlier paper (Engledow(1)). Analyses of certain external factors affecting yield have been recorded by Engledow(2) and by Doughty and Engledow(3).

Description: The fact that the findings of various workers on the influence of weather on yield in oats are seldom in agreement on all essential points suggests that the requirements of the crop varies from province to province, and warrants investigation within regions of relatively narrow compass.

Description: Milk which has been heated to temperatures varying from 105–209° F. for half an hour differs from raw milk in its reaction to rennet in all cases.There is no change in the diffusibility of the nitrogenous substances in milk after heating to temperatures varying from 105–209° F. for half an hour.Heating to 175° F. and above for half an hour appears to reduce the diffusibility of the phosphorus content of milk.Heating to 125° F. and above for half an hour causes marked diminution in the diffusibility of the calcium content of milk.

Description: It has been urged by Bouyoucos (l) and by Haines (2) that soil granulation is caused by the action of water on lumps of partially dried soil, and it is usually accepted that alternate dryings and wettings are largely responsible for the production of tilth. The work described in this article was undertaken to determine whether measurements of the time required for the complete disintegration by water of lumps of dry soil might furnish a reliable method of soil comparison in accordance with these ideas.

Description: In any field of corn the population-density or number of plants per unit length of row is very fluctuating. Accidental circumstances may result in considerable stretches being empty or thinly populated. Quite apart from this, the population of successive short lengths is sharply and characteristically inconstant. Where plants are few tillering is profuse and there is thus a tendency towards constancy in yield per unit length of row. Specific ascertainment has, in earlier experiments, suggested that the tendency is by no means marked. In consequence fluctuation of population-density in the sense here used, reduces yield in typical field crop substantially below the potential maximum appropriate to the soil and other circumstances. From short lengths of row, low in plant-population, yields are low. In aggregate these sparsely populated lengths are a feature of considerable economic importance.

Description: Numerous attempts have been made to devise an experimental method that, applied to a variety or a series of soils, enables them to be placed in an order closely reflecting their field behaviour or their most important physical characteristics. They are called “single-value” determinations as they endeavour to specify the soil by a single number, in distinction to the group of figures obtained, for example, from a mechanical analysis. A number of these methods are discussed in the present paper which contains an account of a detailed investigation on 39 soils of certain single value determinations.The methods selected for study were chosen because (i) they required only simple apparatus, and (ii) they appeared to be related to some distinct soil characteristic.The list of measurements was as follows:Percentage of clay.Moisture content of soil in equilibrium with atmosphere of 50 per cent, relative humidity (the ordinary “air-dry moisture content” which was also determined, is close to this value).

Description: 1. Four White Leghorn cockerels were fed with widely varying quantities of a Sussex ground oats and milk mixture without material alteration in the coefficients of digestibility of the digestible nutrients.2. The amounts fed varied from a sub-maintenance ration of 50 gm. to a “limit of appetite” ration of 150 gm. A slight depression in the coefficients of digestibility of the organic matter, the crude protein and the N-free extract, and a slight increase in the coefficient of digestibility of the ether extract was obtained, but the differences shown are attributed to normal fluctuations in digestibility due to individual variation and not to differences in the quantity of food given.3. In feeding experiments carried out with fowls, in which variable amounts of food are fed, these experiments indicate that it may safely be assumed that the coefficients of digestibility of the food nutrients are not materially affected by the variations in the amounts of food fed.

Description: A Recent statistical survey of the records of premium stallions by Sanders (1) draws attention to the fact that the breeding efficiency of the horse is much below that of the other domesticated animals and that it has apparently declined within recent years. For example, between 1887 and 1889 the average number of mares served by Light Horse stallions and which produced foals was about 59 per cent, of the total mares served. Between 1904 and 1910 this figure had fallen to about 56 per cent, and at the present time is not much above 50 per cent. While this decline may in part be due to the record of infertile services being kept more strictly now than formerly, and perhaps also to the more rigorous conditions to which travelling stallions are subjected, the figures are sufficient to indicate that much loss is actually occasioned by low breeding efficiency and also that there might be considerable improvement on the present standard.

Description: The object of this series of investigations is to secure detailed information concerning the composition, digestibility and nutritive value of pasture grass in its different stages of growth. The results which were obtained in these respects by cutting the herbage of the experimental pasture plot at weekly and at fortnightly intervals have been described in previous communications. During the season of the present experiment, the trials have been carried a stage further by the adoption of a system of cutting at 3-weekly intervals. The main findings of the 1928 investigation are recorded below:(1) Chemical composition of 3-weekly pasture cuts: The adoption of a more lenient system of cutting at 3-weekly intervals led to a slight lowering of the percentage of crude protein in the grass and a slight raising of the percentages of crude fibre and N-free extractives. On the other hand, no corresponding effect was noted in respect of the ether extract, SiO2-free ash, lime and phosphate, the percentages of these constituents being very similar in the weekly and 3-weekly pasture samples obtained in 1928. The falling off of the percentage of crude protein in the 1928 3-weekly-mown herbage, as compared with the weekly and fortnightly-mown herbage of 1925 and 1927 respectively, was not wholly the consequence of the more lenient system of cutting, but was also due in part to the protein-depressing influence of the droughty periods which were experienced in the 1928 season.

Description: 1. There exist in Trinidad large areas of deteriorated soils which have been under cultivation with a single short-term crop for generations. It has previously been established that these soils differ but little from those which still retain their fertility in their content of organic matter. By comparison with the latter, however, they are markedly acidic and so deficient in exchangeable calcium that a material improvement in their lime status appears to be a necessary preliminary to their amelioration. An examination has therefore been made of the means by which this may most successfully be accomplished.2. Determinations of the contents of exchangeable calcium and the pH values of a series of liming experimental plots indicate that:(a) Contrary to experience in England, finely ground limestone has proved a more efficient soil ameliorant than slaked lime.(b) Single relatively large applications of lime fertilisers have given more immediate beneficial results than small annual dressings.(c) The effect of liming appears to have been almost entirely restricted to the depth to which the soil is worked. This is doubtless due to the impermeability and lack of aeration which characterises heavy deteriorated soils.3. A significant increase in crop yield was obtained only on those plots which were later shown to have been rendered neutral in reaction by liming, and on which the degree of saturation of the top 6 in. of soil has been raised to 80 per cent. This value is comparable with that of the fertile soils of Trinidad.4. The experience of liming methods gained in Trinidad may be applicable to other areas of alluvial soils under cultivation in the tropics.

Description: 1. Material is presented which shows month by month the lactation yields of cows in respect of milk and fat. Morning and evening yields are treated separately and differences in relative proportions found.2. Smaller proportions of milk and of fat at the morning milkings are yielded in early lactation by all cows, but this point is most pronounced in heifers and also in heavy yielding cows with relatively small udders. It is suggested that with such animals reabsorption of milk occurs during a long night interval.3. Seasonal variations in yield of milk and fat are shown. It is found that the morning milking does not respond as much as the evening milking to the stimulus to secretion which functions during May and June.4. The quality of milk at different seasons of the year is discussed.

Description: 1. A method for the rapid determination of lime requirements in laboratories equipped with the quinhydrone electrode is described. (10 gm. of soil are mixed in a small wide-mouthed bottle with 40 c.c. of neutral 0·2 M CaCl2 solution. The mixture is then titrated with 0·03 N lime-water in successive portions of 5 c.c, with three minutes' shaking between each addition. The pH value of the mixture is determined after each addition, and the titration continued until the reaction has passed pH 7·0. The results are plotted, and the exact volume of limewater needed to give a final reaction of pH 7·0 is estimated from the graph.)2. The method is compared with the Hutchinson-MacLennan method for a series of soils of different textures and different initial exchange reactions. It appears to yield more reliable results; it is less tedious; it is very rapid, and results obtained thereby can readily be reproduced.

Description: 1. A procedure is described for evaluating an “index of texture” (I.T.), based on determinations of moisture contents at the point of stickiness (P), and of sand contents (S) of soil samples.2. The procedure is simple, and allows of a rapid laboratory examination of a great number of spot samples, so that detailed texture maps can readily be constructed.3. Employed in conjunction with soil-reaction maps, the texture maps form a useful basis for detailed investigations of soil genesis and soil fertility.

Description: 1. Cultures of B. radicicola derived from eight different host plants have been studied and a description is given of the morphology and reproductive processes of the organisms.2. The growth forms described include rods, coccoids, branched forms, gonidangia, gonidia and dwarfed growth, and microcysts.3. The different cell types represent normal stages in the development of the organisms.4. The reproductive processes described are fission, budding, liberation of gonidia, formation of regenerative bodies, and germination.5. The formation of symplasm and the regeneration of cells is discussed.

Description: (1) It is proposed to estimate the amount of organic carbon in soils by determining the amount of sulphur dioxide produced in the ordinary Kjeldahl digestion. The gaseous products of reaction are passed through standard iodine solution, and the excess iodine titrated with standard sodium thiosulphate. Details of the method are given.(2) The results obtained with a number of soils of differing character and origin are compared with the figures obtained for organic carbon by dry combustion. The sulphur dioxide method gives results which average 89.6 ±1.03 per cent, of the combustion figures. It is proposed therefore that the percentage of organic carbon found by this method should be corrected by the factor 100/89.6 = 1.116.(3) The percentage recovery of carbon indicated by the proposed method is rather higher for pure substances but still falls short of 100 per cent.(4) The proposed method is applicable to carbonate soils without the necessity for any correction for inorganic carbon.(5) It is likely that soils containing inorganic reducing substances such, as sulphides will give high results by the proposed method.(6) Absorbing the sulphur dioxide in 25 per cent, sodium bichromate, it is possible to determine the carbon dioxide by passing the gases through standard baryta in a Reiset tower. The organic carbon thus indicated agrees with that by the sulphur dioxide method.(7) From data with certain peats, it appears that the factor 1.724 for converting organic carbon to organic matter is too low.

Description: Inconsistency in the returns of sugar percentages from the factories has often perplexed growers and has at times given rise to some mistrust of the analytical procedure. Consignments of beet lifted on the same day and from the same field have been credited by the factory with widely different sugar contents. This has occurred within the writer's experience, even though the precaution was taken of loading the cart loads of beet into two trucks alternately, thereby eliminating any possibility of one truck being filled with beet from a better part of the field than the other.

Description: 1. Both Pseudoperonospora Humuli and Phytophihora infestans are extremely susceptible in the zoospore stage to the action of weak solutions of soap or saponin. The zoospores are caused to disintegrate suddenly, apparently by changes in surface tension, within 60 seconds, in solutions containing over 0·1 per cent, soft soap. Those of P. Humuli are more vulnerable than those of P. infestans.2. The fungicidal action of soap and saponin mixed with certain adherent substances was tested on hop plants.3. The power of adhesion and the fungicidal efficiency of the mixtures were tested by allowing single drops to dry on the surface of watch glasses and by then adding drops of water containing zoospores.4. Other substances, e.g. aluminium-lime mixture, glycerine, iodine, bromine, were also found to kill zoospores rapidly.

Description: Organic materials with a C: N ratio ranging from about 85: 1 to about 10: 1 were submitted to nitrification tests in an acid and in an alkaline soil during a period of 6 months. In the acid soil only pea pod meal, with a C: N ratio of 13·3: 1 showed an increase in inorganic N over control; in the alkaline soil the limit above which no nitrification will occur within a period of 6 months was at C: N = 26: 1; below this limit the rate of nitrification increased rapidly with decreasing C: N ratio. Unnitrified N was left behind in a quantity corresponding to 1·5–2·2 per cent, of the original material, the percentage being higher in the case of materials rich in N.All the materials tended to increase the content of “a-humus” in the soil, though not to the same extent or in the same manner. More “a-humus” was produced in the alkaline than in the acid soil, except in the case of farmyard manure. Straw, sweet clover, lupin and farmyard manure apparently acted both through their lignin content and through the synthesising action of microorganisms, since they increased the amounts of both N and methoxyl in humus. Mycelium of Polyporus contains a fraction possessing the properties of “humic acid,” rich in N, but devoid of methoxyl, which persists in the soil.

Description: The metabolism of a Berkshire and a Middle White pig has been investigated by means of the calorimeters at the School of Agriculture, Cambridge. The general routine and technique of the observations have been as heretofore.Measurements of the fasting katabolism of each of the two pigs have been obtained in a series extending from an early age to maturity, and the phenomena in general follow the lines of those originally discovered in the Large White; but the fasting katabolism of the Middle White was below that of the Large White earlier studied.The fall in body temperature and in metabolism during the fasts were found to be correlated, and the possible effect of skin colour in this matter is noted.The effect of environmental temperature is investigated and reasons are given for supposing that the critical temperature of the Middle White pig is very low.It is concluded that the existence of a maximum somewhere in the curve showing fasting katabolism per unit area at different ages is necessitated by the two physiological facts (a) that warm blooded animals have to be maintained at a temperature which varies only within very narrow limits, and (b) that the processes of growth are accompanied by waste of energy as heat.

Description: 1. The sugar-cane in Trinidad is subject to blight, caused primarily by the sucking action on its leaves of a Cercopid, Monecphora (Tomaspis) saccharina Dist., commonly known as the “froghopper.” The intensity of the injury sustained by the cane appears to depend largely on the condition of the soil in which it is grown. An investigation has, therefore, been made of the extent to which certain soil factors are associated with the reaction of the cane to froghopper attack.2. The data obtained show that the mechanical composition of the soil and its content of organic matter bear little relationship to the damage caused. The blighted soils differ from those blight-free, however, in that, whereas the former are devoid of calcium carbonate and, as a rule, markedly acid, the latter almost mvariably contain at least traces of this substance, and in general are alkaline or slightly acid only. These differences suggest that the lime status of the soil is a factor of primary importance.

Description: 1. The paper discusses experiments laid down at 39 centres in Great Britain to test the value of seed inoculation for lucerne.2. The seed was inoculated by treating it with a suspension of the nodule bacteria in skim milk containing 0·1 per cent, calcium di-acid phosphate, the method developed by Thornton and Gangulee.3. In the west and north of England the treatment greatly benefited the lucerne and often enabled a crop to be obtained where the untreated lucerne failed. At 12 centres in this area at which the crop was weighed, inoculation increased the yield by over 20 per cent, in all cases save one, where spread of the bacteria vitiated the result.4. The improvement sometimes showed itself as an increased yield and sometimes as an increase in the nitrogen content of the hay. In most cases both these effects were produced.5. In the midland and south central counties inoculation usually produced a temporary improvement, the untreated plant eventually catching up with the inoculated. The effect of inoculation is very much greater where the young lucerne has to compete with a cover crop. Weight results from 8 centres in this area showed increases from inoculation of over 20 per cent, in 4 cases, smaller but significant improve-ment in yield or nitrogen contentin 3 cases, and no significant effect in one case.6. In East Anglia and Kent untreated lucerne usually develops plenty of nodules. An exceptional condition occurred in a trial at Tunstall Heath, Suffolk, on sour light land, where liming and inoculation produced a fair plant although the uninoculated lucerne developed no nodules and failed.7. There is evidence that, when the seed is inoculated, the chances of success with lucerne are on the whole as good in the west and north of England as they are in the south-east.8. In a number of trials sown in 1926 better results were obtained by sowing the seed in a light cover crop in spring than by sowing in June or July.

Description: 1. An account is given of the geology and mineralogy of the soils of a small area characterised by diverse rock groups, which are mainly covered by glacial drift. The topography is also varied. The soils are mainly derived from boulder clay, glacial sands and gravels, and alluvium, the remaining soils being formed on screes and hill-wash. The underlying rocks are lavas of Old Red Sandstone age and sandstones and shales of Carboniferous age.2. A similarity in mineral content of the soils on glacial material and alluvium is shown. All these soils have a high content of fresh ferro-silicates. The soils on the screes and hill-wash are characterised by their content of rock fragments and iron oxides, but minerals from glacial material are also present, though to a minor extent.3. The soils on the drift material contain potash, phosphate and lime-bearing minerals.4. The varied nature of the parent materials has given rise to varied textures in the soils. The soils on the boulder clay are the heaviest, while, the soils on the fluvio-glacial material are very variable.5. The mineral content of the matrix of the boulder clay is similar to that of the local rocks, only the rarer minerals being derived from external sources.

Description: The problem of the use of water by cultivated plants during the period of their growth is of great scientific interest. It is certainly of prime interest for the farmers of a dry region where to secure a yield everything depends in most cases upon the problem of moisture.When studying the problem of the use of water by cultivated plants under field conditions the importance of extremely unstable and widely varying meteorological factors is evident. The fluctuations are especially large and irregular with respect to moisture.

Description: The addition of sodium silicate has been found to increase the yield of barley to a considerable extent, this effect being most marked when no superphosphate is added.The phosphatic content of the ash is not greatly increased in the grain, and is diminished in one case in the straw; the conclusion from this observation that the silicate does not act by releasing soil phosphates, but as a plant stimulus, overlooks the fact that the addition of silica to the ash naturally reduces the percentage of other constituents, and should be discounted.The phosphate removed annually in the crop is greatly increased on the plots receiving silicate, even when this removal has continued for many years without replacement.That additional phosphate is actually made available to the crop on the plots receiving silicate is shown by the increase in the proportion of phosphate in the dry weight of the crop, which appears on all the plots, and at all periods.This increase is quantitatively sufficient to account for the increased yield in grain and straw, without postulating the aid of any stimulus to plant growth.

Description: 1. The form of the dispersion curve obtained by single dispersion treatment below μ/x varies greatly with different soils and with the same soil saturated with different bases. There is no connection between the proportion of very fine material (e.g. below 0·5μ) and other important soil properties. The proportion of the very fine material determined in this way would not, therefore, afford any indication of the “colloid” properties of the soil. If the proportion of fine material were estimated by a decantation method the results might be substantially modified.2. Under the same conditions of dispersion sodium soil is better dispersed than ammonium. Sodium carbonate should therefore be the best medium for mechanical analysis.3. No case has been met with where the proportion of clay found is affected to an important degree by the use of hydrogen peroxide.4. With no soil tried was the number of decantations reduced by the use of acid pre-treatment; those examined gave the same clay content i f sufficient puddlings with sodium carbonate were used with or without acid.5. No method has been found whereby certain soils can be dispersed i n a single operation as is required in the pipette method. In some cases this is due to gypsum, but there are others in which the cause of the difficulty of dispersion is not yet known.6. In the cases examined sodium carbonate gives a higher result than ammonia when using the International pipette method.7. For Sudan soils decantation methods appear essential, hydrogen peroxide unnecessary, acid pre-treatment not essential, and sodium carbonate better than ammonia. We are of opinion that the same holds good for many other soils.

Description: A practical adaptation of a method devised by Miss Glynne for testing indoors the immunity or susceptibility of potato varieties to wart disease is described. The method consists of infecting by summer sporangia the young sprouts of the tubers under test. Extensive test has given such satisfactory results that there is little doubt that the method is infallible.The writer wishes to render his grateful thanks to Mrs N. McDermott, who has been actively associated with him throughout the work described and who is largely responsible for the technique employed; to Miss M. D. Glynne, of the Rothamsted Experimental Station, for her many helpful suggestions; to Mr W. H. Parker, Director of the National Institute of Agricultural Botany, Cambridge, for his assistance and advice; t o Dr R. N. Salaman for supplying material for test, and to Dr G. H. Pethybridge for his kindness in examining tubers sent to him.

Description: 1. The interaction of Bordeaux mixture with lead arsenate and with calcium arsenate has been studied by an examination of the effects which are produced:(a) When hydrated lime is added to the arsenical compounds.(b) When copper sulphate is added to the arsenical compounds and hydrated lime.2. The nature of the interaction of calcium hydroxide and diplumbic hydrogen arsenate has been shown to be most complex and to result in the complete decomposition of part of the lead arsenate and th e formation of basic calcium arsenates.3. Support is not given to the view that calcium carbonate decomposes diplumbic hydrogen arsenate with the production of soluble arsenic compounds.4. When the lead arsenate, in water, is allowed to interact for long periods with excess of hydrated lime, the amount of basic calcium arsenates formed is such that large quantities of arsenic are brought into solution by the action of carbon dioxide.5. Under conditions when the calcium hydroxide is rapidly converted to the carbonate the amount of arsenic rendered soluble is slight.6. The conclusion is formed that in actual spraying there is a definite reduction of the risk of arsenical injury when hydrated lime is added to lead arsenate and to calcium arsenate.7. It is concluded that when the conditions are such that the addition of hydrated lime brings about a reduction of arsenical injury, the use of an “equal-lime” Bordeaux mixture containing an equivalent amount of calcium hydroxide will prove far more effective.

Description: (1) Digestibility trials with wheats, carried out with White Leghorn cockerels, indicate that “weak” and “strong” wheats are equally suitable as sources of supply of food nutrients for poultry.(2) In the production of wheat for poultry feeding, yield rather than strength should be the primary aim of the grower.(3) Further research work on the Katayama method of estimating the digestibility of poultry feedingstufls is indicated.(1) Digestibility trials with “whole” maize and “flaked” maize indicate that steam cooking by commercial processes considerably increases the digestibility of the food nutrients in maize. (2) The view held that the fowl is akin to the pig so far as its powers of digestibility of low fibre foods are concerned is substantiated by the results of the trials here reported.

Description: From the results presented it may be permissible to point out the following:Fungi are responsible for the fixation of very small quantities of nitrogen, while the Azotobacter and B. amylobacter groups are the important nitrogen fixers in the soil.B. amylobacter is able to fix from 4 to 5 mg. of nitrogen per gm. of dextrose consumed.B. amylobacter has an optimum range of pH. between 6·0 and 7·0, and Azotobacter between 7·0 and 8·4.Azotobacter utilises the organic acids produced during the fermentation of dextrose as sources of energy for nitrogen fixation in the absence of dextrose. B. amylobacler does not, or does only to a limited extent, utilise such products.Large quantities of dextrose do not favour an efficient nitrogen fixation, as large quantities of the organic acids produced effect the reaction of the media rendering the organisms inactive.The nitrogen fixing organisms seem to be equally well represented in the heavy and light soils.

Description: In a previous paper Quinlan(1) published the results of his observations on a flock of sheep which had been vasectomised for two years. The present paper contains a résumé of the data already published, to which an additional twelve months' observations have been added. This paper gives the data available from observations carried out on the flock over a period covering three years, or a period of time which allowed full skeletal development to take place.

Description: The nature of the problem of moisture determinations on materials such as flour and wheat is discussed shortly. It is not possible to obtain by over drying true values for moisture contents. What is sought is a convenient and reliable procedure giving strictly reproducible figures possessing full comparative value. This was the object of the work described, the main lines of which should be applicable to agricultural products of many kinds.The electrically heated air oven is the most convenient and suitable instrument for routine purposes, and comparative results show that it allows of far more reliable work than the water oven.Determinations of apparent moisture content have been made on a sample of wheat flour in electric ovens at temperatures ranging from 90° to 140° C. and for periods of heating ranging from 1 to 14 hours, the technique and number of determinations (about 400 altogether) being such that the results were suitable for statistical examination. The probable errors of single determinations were calculated for several sets of results and did not exceed 0·05 per cent. The results given show that at several temperatures, variation in time of heating over a considerable range does not affect the values obtained. In the light of these results it was possible to assess the reliability, as well as the convenience, of various possible procedures.

Description: An account is given of studies of moisture content in the field. The results are in agreement with Joseph's (1) view that the relation between salt content and fertility is chiefly due to the effect of sodium salts on soil texture. At the Gezira Research Farm a single watering moistens only the top 3 ft. of soil, although in the course of an irrigation season some small percolation continues below this depth. The water requirement of cotton in this region is extremely high and danger of water strain is correspondingly acute. The effect of 14 days' flooding is taken as a measure of permeability in the field and this test was applied with confirmatory results to two areas whose agricultural value had previously been gauged both by laboratory studies and by field observation of the soil profile. The genesis of the Gezira soil is briefly discussed with regard to the relation between salb content and fertility and with regard to the use of gypsum as a corrective. Marked improvements in permeability have been brought about by applications of this substance.I am indebted to Dr A. F. Joseph, under whose direction this work was done, for his useful suggestions and for facilities placed at my disposal.

Description: The object of the investigation which has been described in the present communication has been to secure information concerning the feeding value of sugar beet pulp as produced at the present time in this country. Data have been obtained respecting:(1) The composition and digestibility of wet sugar beet pulp.(2) The composition of dried sugar beet pulp and the digestibility of this feeding stuff when fed to ruminants (a) in the dry condition, and (b) after preliminary soaking in water.(3) The composition of molasses-sugar beet pulp.Data have been given showing the amounts of sugar beet by-products which are becoming available for use on the farm.The commercial processes of drying wet sugar beet pulp, and the method of manufacture of molasses-sugar beet pulp, have been described.It has been shown that crude fibre (20.3 per cent.) and N-free extractives (65.7 per cent.) constitute together more than four-fifths of the dry matter of sugar beet pulp, the latter being deficient in respect of protein, ash and oil. The carbohydrate of sugar beet pulp is invested with, special interest, being mainly in the form of pectose. A short account of the chemistry of the pectic substances has been given.

Description: (1) Exchangeable magnesium and potassium can be determined in carbonate-free soils by the use of 0.5 N acetic acid as a leaching agent.(2) A method is described for the determination of the total exchangeable bases present as acetates in the leachings.(3) The results obtained by this method differ from those obtained by summation of separate determinations by an amount equivalent to the sulphates and chlorides present.(4) It is suggested that the total exchangeable bases by the proposed method gives a truer measure of the exchangeable bases than methods in which bases present as sulphates and chlorides are also reckoned in.

Description: 1. The day to day variability in the yield of milk and fat of cows is affected by many factors, two of which are stage of lactation and season of the year. Variability is high during the first month of lactation (particularly during the first few days after the calf is weaned), but after this a fairly constant variability may be expected. Under the conditions of management in the herd under discussion and probably in most herds in Southern England variability is highest during the month of May and also tends to be higher during the summer than the winter months.2. A method is presented of calculating the variability in the yield of mixed milk from a herd of cows and the error to be expected when milk records and fat percentages of individual cows are calculated from a few samples.3. When cows are milked twice daily at unequal intervals the yield of milk obtained in 24 hours is slightly less variable if a morning milk yield is added to the subsequent evening yield, than if an evening yield is added to the subsequent morning yield.

Description: 1. The acid method previously described has been used to evaluate samples of pyrethrum derived from both Swiss and Japanese seed, with equally successful results.2. A rapid method for the evaluation of pyrethrum by a determination of pyrethrin I is described.

Description: (1) Animals on a calcium-deficient diet suffer periodically from loss of appetite though the ration is in every other respect satisfactory.(2) The results of twenty-two digestion trials show no enhanced effect on the digestibility of the organic constituents of the food on adding calcium carbonate to a lime-deficient ration.In conclusion, I wish to express my thanks to Prof. T. B. Wood, F.R.S., for giving me the necessary facilities to carry out the work; to Mr H. R. Davidson, M.A., for placing the experimental animals at my disposal and also to Dr H. E. Woodman for his active interest and supervision at all stages of the work.

Description: A regular optimum spacing among plants is the theoretical ideal. Regularity is difficult to secure and the ever varying optimum is not determinable. But earlier investigations have shown that field crops of corn are marked by extremely high fluctuation in population density along the rows of plants; and further, that in this fluctuation lies an important limitation to potential yield. Wider knowledge of this limitation is being sought. The experiments have clearly confirmed plant density fluctuation as a characteristic of field crops (of wheat). Measures of this fluctuation and analyses of its nature and causes are the subject of the paper.In relation to plant development and yield, fluctuations in density or spacing from point to point along the row, are the most important features associated with drill action. These have been measured by counts, both of seeds and of plants, on unit lengths of row. Such “census” counts are described in detail for four normal fields. Plant counts were made periodically. In general a unit length of one foot of row was adopted. For analytical purposes the refinement of a per-inch count proved necessary.Fluctuation in seeds deposited per foot may be illustrated by the data from one of the fields. The mean was 18·0 and the standard deviation was 7·2. In aggregate the field could be regarded as consisting of five equal portions (quintiles of the per-foot distribution) for which:Number of seeds per foot = 5·0–12·2; 12·2–15·0; 15·0–18·0; 18·0–22·3.Equivalent seeds rates (bushels per acre) = 1·42; 2·00; 2·35; 3·11; 3·70.The distribution per inch, determined by a specially devised method, is illustrated for two fields in Diagram I. Four equal aggregates (quintiles of per-foot distribution) from one and the same acre had the widely different seedings displayed in Diagrams II and III.

Description: 1. Of a large number of cultivated soils examined, chiefly from the south-east of Scotland, the majority had a pH between 5 and 6·5, a “lime requirement” of 0·05 to 0·25 per cent. CaCO3 and an exchangeable calcium content of 0·1 per cent, to 0·45 per cent. CaO.2. A general agreement was observed between these three sets of figures although numerous exceptions occurred.3. The reaction of a district of six square miles was studied in detail and of a single farm in still greater detail.4. Long unploughed soils were found to have a low pH, a low content of exchangeable calcium and a high “lime requirement.”5. Woodland, hill and heath soils were characterised in their surface layers by an extremely low pH (below 5 as a rule), a low content of exchangeable calcium (usually less than 0·1 per cent. CaO) and a high “lime requirement.”

Description: The scheme of soil classification which finds most favour among scientists to-day has come from Russia and is the work of a band of brilliant and enthusiastic investigators whose labours have brought some order to what was otherwise chaos. The object of this communication is to endeavour to show how it is possible to modify the views of this school so as to make them apply to British conditions, and how the majority of British soils may be brought within the envisaged scheme.

Description: (1) The physiological effects of calcium-deficiency on pregnant sows are briefly discussed. Results are given which demonstrate that a deficiency of lime in the food has no detrimental effect on the live weight of the young piglings at birth thus showing that up to parturition it is the mother organism that suffers and not the offspring.(2) Storage of nitrogen takes place throughout pregnancy but the results indicate a considerably enhanced conservation within three weeks of parturition. The average daily retention of nitrogen by the high-calcium group of sows was 12·51 gm. and by the calcium-deficient group 9·78 gm. The normal sows therefore stored 1439 gm. N and the calcium-deficient 1125 gm. N during the gestation period. It is shown that storage of protein during pregnancy is greatly in excess of the foetal requirement, so that the mother organism, during gestation, adds on a reserve supply of protein in preparation for parturition and lactation.(3) Ash ingredients were retained at all stages of gestation by both groups of sows. The addition of calcium carbonate to the food, however, resulted in an increased retention of ash. The percentage of the ash intake in the faeces was very similar in both groups, but the percentage of the intake in the urine was distinctly higher in the calcium-deficient sows indicating a more economical utilisation of ash by this group.

Description: (1) A solution of dicalcium hydrogen arsenate at a strength of 0·0125 per cent. As2O5 was fungicidal to the conidial stage of Sphaerotheca Humuli, while at 0·006 per cent. As2O5 it was not quite fungicidal.(2) Lime casein containing calcium hydroxide when added as a spreader to calcium arsenate was shown to reduce the fungicidal properties of the calcium arsenate spray.(3) A solution of calcium thioarsenate at a strength equivalent to 0·006 per cent. As2O5 was fungicidal to the above fungus, while at 0·003 per cent. As2O5 it was below fungicidal strength.(4) It is suggested that the increased fungicidal properties of the mixed lime sulphur-lead arsenate spray are due to the presence of calcium thioarsenates.

Description: The development is recorded of the series of experiments with potatoes at Rothamsted during 1925–27, designed to examine the quantitative response of yield to varying quantities of nitrogenous and potassic manures, and to test the relative value with this crop of different sources of potash.While rather precise comparisons were obtained on the qualitative question by means of Latin squares in 1925–26, the reality of the depression ascribable to chloride could not be demonstrated in these years, but became clearly apparent when in the following year, the qualitative experiment was merged with the quantitative one.In the earlier quantitative experiments, although satisfactory responses were obtained, the precision of the results left much to be desired, since only four replicates could be used. When by merging the experiments this was increased to nine replicates, much smaller responses were clearly measurable.The large and complex type of experiment finally adopted thus supplied more precise information on both heads than could previously be obtained, and in addition to a more thorough exploration of the different combinations possible.

Description: An attempt was made in a recent communication (1) to propound a theory in connection with the digestion of cellulose in the ruminant organism which should be compatible with Kellner's findings as to the value of digestible fibre in the fattening of ruminants. It was shown that the generally accepted theory, that cellulose is digested by bacterial agency in the rumen with the production of organic acids and gaseous products, such as methane, hydrogen and carbon dioxide, failed entirely to account for the equal values of digestible fibre and starch for fat production in the ruminant animal. This could only be explained by assuming that glucose (or some other sugar capable of hydrolysis to glucose) was formed as a primary product of the action of bacteria on cellulose, and that, as with digestible carbohydrates originally present in the food, only about 8 per cent, of the sugar so formed underwent further bacterial breakdown into organic acids and gases, the remainder being available for absorption into the organism in the form of glucose. On this assumption, it would follow that every gram of fibre so digested would yield to the organism as much glucose as would a gram of starch, and in this way Kellner's practical finding would be capable of explanation.

Description: Data are recorded concerning the phosphorus partition of the blood of cattle grazing over phosphorus deficient pasture of the Union of South Africa. The outstanding characteristic is low inorganic phosphorus, with a correlated reduction in total phosphorus.When a small ration of bone meal is given to the cattle, comparatively normal figures are shown. Heifers approaching two years in age, supplied with bone meal from weaning onwards, show a normal inorganic P fraction of 5 mg. per 100 c.c. of blood. Control heifers without bone meal show 2·3 mg., or less than half. Control cows may drop to 1 mg., or even lower. Calves of control mothers are normal so long as milk supply is adequate, but may show reduced inorganic P if aphosphorosis of the mother is acute. In general, low inorganic P in the blood is associated, with poor condition of the animal. Rapid colorimetric determination of inorganic P in the blood of the grazing animal, easily obtained from the jugular vein, provides a simple means of detecting phosphorus deficiency in the pasture.Although long-continued phosphorus deficiency leads to the clinically recognisable disease “Styfsiekte,” especially in lactating animals, the less pronounced deficiency, manifested as malnutrition and stunting of growth, without direct mortality, is detected by blood analysis with equal certainty.

Description: This paper describes a statistical analysis of the records collected by the Norfolk Milk Recording Society (3918 lactations), comparing the results with those obtained from the records of the Penrith M.R.S. (already published).As in the case of Penrith, autumn calvers were found to average more milk in a lactation than spring calvers, but the best months of calving were two months later—i.e. October to February instead of August to December; this is because in the case of Norfolk, yields are maintained well throughout the winter, whereas they fall off very rapidly in the Penrith district from February to April, and if this bad period comes early in the lactation a low yield results. The yield falls off, in both districts, very rapidly during summer (after the flush of grass in spring) and particularly during the two periods June-July and September-October; the average rates at which the yield declines during different calendar months, appears to provide the explanation of the variation in yield according to the month of calving. Seasonal variations appear to be nutritional, rather than meteorological, in nature, and it seems probable that with more knowledge of feeding and management they should be largely eliminated; the greatest scope for improvement lies in summer, when it is suggested arrangements should be made for a supply of catch-crops for feeding green, and this supplementing of the grass should begin much earlier in the year—i.e. beginning of June in normal seasons—than is generally believed.

Description: (1) A gasometric method for the determination of organic carbon in soils by the use of sulphuric-chromic acid mixtures at 100° C., as suggested by Watts in 1902, is described, and recommended for use in routine soil analysis.(2) The method is compared with the Kjeldahl procedure recently introduced by Robinson, McLean and Williams, and is found to give results which are generally similar, though numerically slightly lower.(3) The wet combustion method is somewhat simpler than the Kjeldahl method, but it has the disadvantage that nitrogen determinations cannot be made simultaneously, so that its usefulness in studies on soil organic matter is decidedly less.

Description: Age, it will be remembered, is here measured in lactations, but little error is involved if the true age in years, at the commencement of the lactation, is taken as two more than the number of the lactation—e.g. a cow, on the average, calves her third calf when she is roughly 5 years old.

Description: Experiments were carried out at two centres in Leicestershire during the spring of 1928, with the object of comparing the values of mangels and dried sugar beet pulp in the winter ration of dairy cows.Two groups of cows were selected at each centre, and the usual method of feeding for a period on one ration and then reversing, was adopted. Composite samples of the milk from each group of cows were taken at six consecutive milkings per week, during the period of the experiment. Determinations of fat and solids not fat were made, and the yield of milk at each milking recorded.Although there are indications that the change of ration caused a slight temporary variation in the quality of the milk, the secretion of milk solids followed, in a general way, the variation in yield: This is confirmed by the average composition figures representing the whole of the milk from each particular ration.Thanks are due to Mr Thos. Hacking for placing every facility for obtaining these data at the disposal of the author.

Description: The investigation bears out the conclusion of the Rothamsted experiments that leaching out may occur any time throughout the winter up to March, or rarely April.The loss of nitrates is directly limited by the amount of drainage and so is indirectly determined by the rainfall, and by temperature—as it affects the rate of evaporation.All three nitrogenous fertilisers are shown to lose well over 50 per cent, of a normal dressing by leaching out during the winter, but the loss is greatest in the case of sulphate of ammonia, least in the case of rape dust, calcium cyanamide being intermediate.The writers wish to express their indebtedness to Miss N. Sugg who carried out the experimental work in the first winter.

Description: In the past the standard method for determining the chloride content of soils has been to titrate with silver nitrate using potassium chromate as indicator. In most cases, the soil must be filtered through a filter candle and where in favourable cases filtration can be dispensed with, it is necessary to wait until the soil has settled before aliquot portions can be pipetted off and titrated.

Description: In a field trial with lucerne grown from seed treated with varying doses of culture it was found that the numbers of nodules were increased as the dose was raised from 2,500 to 20,000 organisms per seed (56 to 7 Ib. of seed per culture). Storing the seed for periods up to 28 days between inoculation and sowing, caused some loss in the nodule numbers. This loss was greatest between 1 and 7 days' storage.The difference in dose of culture and in period of storage did not significantly affect the crop subsequently obtained from the inoculated plots, whose yield was, however, much above the uninoculated.In a pot experiment made with runner beans, it was found that increase in the dose of culture above 1,280,000,000 organisms per pot containing six seeds was still capable of increasing nodule numbers but not to an extent proportional to the increase in dose.The experiment does not exclude the possibility that the restriction in effect of very heavy doses may be due to the soil population becoming saturated with the bacteria. On the other hand, observations on lucerne plants grown aseptically on agar and inoculated with a pure culture, showed that even when excessive numbers of the bacteria immediately surrounded the root hairs, only 4 per cent, of these were infected.

Description: 1. (a) Pyrethrin I and II have been isolated by the method of Staudinger and Ruzicka from the insecticidal plant Pyrethrum (Chrysanthemum cinerariaefolium). Both are shown to be highly toxic to the insect Aphis rumicis.(b) Pyrethrin I was found to be the most toxic substance so far tested by us and, as it was about ten times as toxic to these insects as pyrethrin II, it is concluded that it is mainly responsible for the contact insecticidal value of pyrethrum.2. Two micro-analytical methods of determining the pyrethrin content are described, (a) By means of the acids after hydrolysis, (b) By means of the semicarbazone. They are given on pp. 278, 282.3. The analytical results obtained for a series of pyrethrum samples agreed with their observed insecticidal properties to Aphis rumicis.4. Comparisons of the pyrethrin contents, as estimated, with the results of direct toxicity experiments both on the pyrethrum samples and the pure pyrethrins, confirm the validity of the analytical methods.5. There was a significant and positive correlation, in the samples tested, between the amounts of pyrethrin I and II.6. Insufficient data are available to show a significant correlation between the size of flower-heads and the content of poison, or to draw conclusions as to the effect of external conditions such as soil, weather or age of bed.