ALBERT

Description: 1. The Woburn field experiments on wheat after green manures are briefly reviewed. Contrary to the original expectations the wheat was less good after two summer crops of tares than after two mustard crops. This result was obtained many times and in recent years the wheat yields were extremely low after both green manures.2. Regular soil analyses for nitrate and ammonia through 1928 and 1929 showed that the mean nitrate content was extremely low (1·2 parts of nitric nitrogen per million of soil). During the cold dry winter of 1928–9 the ammonia nitrogen was several times greater than the nitrate nitrogen.3. Further evidence of an acute nitrogen deficiency during the critical period for the wheat plant in May and June was afforded by the large responses to top dressings of sodium nitrate both in the 1929 and the 1930 wheat crop.

Description: 1. It is suggested that the striking failure of winter wheat grown in rotation with two summer crops of tares or mustard on the sandy soil the Woburn Experimental Station is due to the production of nitrate and ammonia from the green manures at times when the wheat is unable to use them efficiently and to the consequent loss of nitrate in the drainage. Owing to its low C: N ratio the nitrogen in tares nitrifies very rapidly and the loss by leaching is very great. Mustard, on the other hand, reduces the winter loss, but the nitrogen present in the mustard and that absorbed in the decomposition of the excess carbon compounds are liberated too slowly to be utilised efficiently by the wheat and much of the nitrate subsequently produced is also lost by leaching.

Description: 1. A total of forty-two Suffolk cross-bred and 230 stud Romney Marsh ewes were used in four experiments in which pregnant mare serum gonadotrophin (p.m.s.) was used in various combinations with progesterone and oestrogen in attempts to induce fertile mating in anoestrus.2. Groups of six Suffolk cross-bred ewes were injected with 1000 i.u. p.m.s. after pretreatment, commencing 4 days earlier, with 75 mg. progesterone administered in one of four different ways. Six twice-daily injections in oil resulted in oestrus in five ewes in each of two groups treated. Single injections in oil solution, aqueous suspension, and benzyl alcohol emulsion resulted in oestrus in two, nil, and four ewes, respectively. All were served within 48 hr. of injection of p.m.s.3. Ovulation was observed in five of six crossbred ewes which received six twice-daily injections of progesterone in oil, without subsequent injection of p.m.s. Three were served.4. Divided injections of progesterone commencing 4 days before 750–1000 i.u. p.m.s. failed to induce a satisfactory oestrous response in Romney Marsh ewes. An increase to 7 days in the duration of progesterone stimulation resulted in oestrus in all of eighteen ewes treated.5. The injection of a benzyl alcohol emulsion containing 75 or 150 mg. progesterone, given as a single dose 4 or 7 days before 750 i.u. p.m.s., failed to induce a satisfactory oestrous response. Of seventy-two ewes treated, only seven were served.6. Lambing results were most unsatisfactory when progesterone-p.m.s. treatment was followed by artificial insemination. Of 144 Romneys inseminated, only twelve lambed. Successful pregnancy appeared unrelated to the type of treatment or the occurrence of oestrus.7. On the basis of the oestrous responses observed after the injection of a variety of combinations of oestrogen, progesterone, and p.m.s., and by reference to quantitative data on progesterone-oestrogen relationships in oestrous behaviour in the spayed ewe, it is concluded that the developing follicle of the Romney Marsh ewe produces an amount of oestrogen approximately equivalent, in its physiological activity, to a single injection in oil of about 20 μg. oestradiol benzoate.

Description: A RECENT communication from Mr. E.H. Davison relating to the possible age of the “ Lundy Island granite ” is interesting as affording several points of contrast with the results of detailed researches in structural and petrological characters of this some-what inaccessible island in the Bristol Channel, which the author has been carrying out for some time.

Description: Summary1. The loss of activity of pyrethrum flowers and preparations has been studied.2. The degree of concordance between the content of pyrethrin I, as determined by the acid method, and the insecticidal value of pyrethrinised dusts, before and after exposure to air and artificial illumination, has been statistically examined. The pyrethrin I values, corrected for a small residual amount of extraneous matter, indicate fairly closely the degree of activity of the samples. The loss of pyrethrins on exposure has been traced out quantitatively.3. A comparison was made between two samples of pyrethrum flowers, one rich and the other poor in pyrethrins, in order to determine the degree of concordance between the pyrethrin I content and their toxicity. The pyrethrin I value as determined by the acid method, subject to a small correction, gave a good indication of the relative activities of the samples.

Description: 1. The analytical methods of Tattersfield, Hobson and Gimingham(6) and Gnadinger and Corl(1) for the determination of the pyrethrins in pyrethrum flowers are compared, and certain modifications in technique suggested.2. Good concordances have been obtained between analytical data and insecticidal tests employing Aphis rumicis.3. A new method for the rapid and approximate evaluation of unadulterated samples, employing small quantities of material, is described.4. Observations on the pyrethrin content of individual flowers in the various stages of development are recorded, making use of a modification of the method indicated under (3).

Description: In most work on the theory of stability of laminar flow, infinitesimal disturbances only have been considered, so that only the initial growth of the disturbance has been determined. It is the object of the present paper to extend the theory to larger amplitudes and to study the mechanics of disturbance growth with the inherent non-linearity of the hydrodynamical system taken into account. The Reynolds stress (where averages are taken with respect to some suitable space coordinate) is the fundamental consequence of the non-linearity, and its effects can be anticipated as follows. Initially a disturbance grows exponentially with time according to the linear theory, but eventually it reaches such a size that the transport of momentum by the finite fluctuations is appreciable and the associated mean stress (the Reynolds stress) then has an appreciable effect on the mean flow. This distortion of the mean flow modifies the rate of transfer of energy from the mean flow to the disturbance and, since this energy transfer is the cause of the growth of the disturbance, there is a modification of the rate of growth of the latter. It is suggested that, in many cases, an equilibrium state may be possible in which the rate of transfer of energy from the (distorted) mean flow to the disturbance balances precisely the rate of viscous dissipation of the energy of disturbance. A theory based on certain assumptions about the energy flow is given to describe both the growth of the disturbance and the final equilibrium state, and application is made to the cases of Poiseuille flow between parallel planes and flow between rotating cylinders. The distorted mean flow in the equilibrium state can be calculated and from this, in the latter case, the torque required to maintain the cylinders in motion. Good agreement is obtained with G. I. Taylor's measurements of the torque for the case when the inner cylinder rotates and the outer cylinder is at rest. © 1958, Cambridge University Press. All rights reserved.

Description: 1. Superphosphate, at two levels and three intervals of application, was applied to calcareous downland pasture grazed by sheep over a period of 3 years.2. At the high level, total dry-matter and crudeprotein yields were higher from a single initial application and from thrice-yearly applications than from annual applications.3. At the high level, mean herbage phosphate content and total phosphate yield were higher following a single initial application than when superphosphate was applied at shorter intervals.4. Superphosphate increased the cover of grasses and legumes and reduced the cover of herbs.5. Superphosphate affected the cover of individual species in the following manner:(a) Favourably: Dactylis glomerata, Festuca rubra, Arrhenatherum elatius, Poa trivialis, Holcus lanatus, Lolium perenne and Trifolium repens.(b) Unfavourably: Agrostis stolonifera, Leontodon spp., Prunella vulgaris, and other minor herbs.(c) No measurable effect: Poa pratensis, Plantago lanceolata, Ranunculus bulbosus and Crepis capillaris.

Description: An experiment is described in which 64 individually-fed pigs were used to investigate the effects of dietary protein status, administration of aureomycin and hexoestrol implantation on growth, efficiency of feed utilization and carcass conformation. The results of hexoestrol implantation and interactions with the other two variables only are reported here. The pigs were implanted at 120 lb. and again at 150 lb. and killed at 200 lb. live-weight.The main features of hexoestrol treatment were:1. Body length taken from the anterior edge of the aitch bone to the junction of first rib and sternum was significantly increased by 9·75 mm.2. The percentage lean in the carcass was increased by 0·82%, representing approximately 1¼ lb. more lean meat in a 155 lb. carcass. The water content of the lean was increased but not significantly.3. Body fat was reduced but this was not reflected in a significant change in back fat measurements.4. No changes could be detected in the thyroid or adrenals, but whereas male castrates showed little effect of treatment on other organs apart from a certain amount of urethritis, the intact female manifested major changes in the genital tract. The uterus in particular was greatly enlarged and ovarian activity obviously reduced. The implications of these effects are being examined.5. There was no response to treatment in terms of growth rate or efficiency of feed utilization.

Description: An experiment is described in which sixty-four individually-fed pigs were used to investigate the effects of dietary protein status and administration of aureomycin on growth, efficiency of feed utilization and carcass conformation.The main features of the results obtained were:1. Pigs fed a ‘standard’ protein diet showed superior performance in terms of growth and economy of feed utilization in comparison with a ‘substandard’ ration. Appreciable differences in carcass quality including reduction in backfat and total body fat, concomitant with an increase in the lean meat content also resulted from variation in ration protein content. These results have been discussed in terms of the possible significance of both dietary crude protein status and amino acid content.2. The administration of aureomycin at a ‘nutritional’ level had no apparent effect on any of the indices of pig productivity subject to analysis.3. The high killing percentages noted over-all, have been discussed in relation to dietary energy and fibre levels.