ALBERT

Notizen: SYNOPSIS. When two strains cf T. pyriformis that do not require exogenous pyridoxine are crossed, all progeny grow without the vitamin. Offspring from crosses of two pyridoxine requiring clones require pyridoxine with the exception of a few which will grow without pyridoxine. The ratio is approximately 3:1 favoring the pyridoxine requiring category. In matings involving the homozygous dominant pyridoxine requiring clones with the double recessive mutant, that is +/+ X p/p, all of the resulting progeny need pyridoxine. Test crossing these heterozygotes (+/p) with the parental pyridoxine non-requiring clones (p/p) gives offspring approximating a 1:1 ratio. Matings between two heterozygotes derived from breeding experiments also yield progeny in approximately 3 pyridoxine requiring: 1 pyridoxine non-requiring. All data indicate selection for the heterozygote in the population and a possible selection against either homozygote. The great abundance of heterozygotes and rarity of recessive homozygotes in natural habitats corroborates these findings. The genetic evidence supports a single gene hypothesis although the possibility of multiple closely linked genes cannot be ignored. There is also the possibility that a dominant suppressor gene may function in blocking the activity of the pyridoxine mutant genes. Moreover, if this gene exists it may be incompletely dominant since the heterozygote grows slightly on deficient media.

Notizen: SYNOPSIS. Trichodina urinicola was found in newts, Triturus cristatus and T. taeniatus, in three localities in Czechoslovakia. The ciliate populations showed important differences on the basis of which they were separated as three new forms of this species: T. urinicola f. typica, T. urinicola f. bohemica, both from Triturus cristatus, and T. urinicola f. taeniatus from Triturus taeniatus. The great variability of trichodinids is evident from the literature as well as from our own observations, so that these new forms are to be regarded as provisional ones until it is possible to decide on the basis of a large number of observations the extent of specificity and variation of individual endozoic species of Trichodina. A detailed description of these forms is given as well as a comparison with the known species of trichodinids inhabiting the urinary tract of amphibians. A brief comment on the present taxonomy of the Urceolaridae in general is outlined.The need for a uniform description of these ciliates is emphasized; in connection with this, the taxonomic value of individual body characters is discussed. Special attention is paid to the adhesive disk of Trichodina, the structure of which is of greatest importance in the taxonomy of this group. On the basis of Dogel's and Fauré-Fremiet's descriptive methods employed in study of trichodinids, a proposal of a uniform description of Trichodina is made which involves all the important features of these protozoa.

Notizen: SYNOPSIS. Several substrains of Euglena gracilis var. bacillaris made chlorotic by treatment with pyribenzamine or streptomycin, or by growth at high temperature (35–36°C.), have been examined for their carotenoid content. They differ from the normal green strain both qualitatively and quantitatively. Some strains produce no detectable carotenoids while the carotenoid concentration in the strains producing most is at best only one-fifth that of the normal strain. In all substrains producing carotenoids, the carotene fraction consists of β-carotene accompanied by some members of the phytofluene series. In only two of these substrains, HB-G and PBZ-G3, are xanthophylls produced in significant amounts. In HB-G, the main pigment is echinenone, and in PBZ-G3 it is zeaxanthin. The significance of these findings is briefly discussed.

Notizen: SYNOPSIS. Association of gamonts of Pyxinia crystalligera takes place in the midgut of its beetle host, Dermestes vulpinus. At 25°C. the development of gametocysts to the point of liberation of sporocysts is completed between about 15 hours and 27 hours after the gametocysts are deposited with fecal material. Dehiscence is favored by relative humidities of 0% to 90%, but is not favored by a relative humidity of 100%. During the early development of the gametocysts outside the host, the crystals and paraglycogen granules in the cytoplasm of the associated gamonts become concentrated in large masses. The gametes are formed at the periphery of the gamonts. After fusion of the gametes takes place and the sporoblasts begin to develop, the residual cytoplasm containing the inclusions moves outward to form a continuous layer next to the gametocyst envelope, so that the sporoblasts become crowded into a central core. A few hours before dehiscence is initiated a clear area appears on the upper side of the gametocyst. The contents of the gametocyst begin to shrink away from the envelope except in the region of the clear area. Eventually the sporocysts emerge through the clear area and press against the envelope of the gametocyst, causing formation of a conical papilla in the envelope. With continued pressure from the sporocysts, the papilla ruptures at its tip, and the sporocysts emerge in a continuous thread until dehiscence is completed. The thread of sporocysts may attain a length of about 11 mm.

Notizen: SYNOPSIS. The steps leading to purine ring closure were examined in Strigomonas oncopelti. The flagellate has an obligate adenine requirement (hypoxanthine and guanine are inert) when grown without p-aminobenzoic acid. The imidazole counterpart of adenine but not the imidazole counterpart of hypoxanthine was active. A pathway for purine biosynthesis compatible with these results is sketched.

Notizen: SYNOPSIS. The Nuttallia of the gerbil is transmitted by Rhipicephalus secundus only if the infected meal is taken by the larva, and the subsequent nymphal stage is the only one which is able to infect. There is no transovarial transmission.Infective trophozoites remain in the larval caeca for about 12 hours after gorging. The infective nymph is able to give rise to new infections at various times after it has been allowed to feed, but never later than the third day after disengagement from the host.

Notizen: SYNOPSIS. The process of autogamy in unassociated individuals of Paramecium polycaryum was reported by the author in 1954. In May, 1955, conjugation was first seen in this species in cultures collected by me at Annamalainagar, South India, thus removing it from the list of non-conjugating species. This appears to be the first instance in which the process of autogamy was detected prior to observation of conjugation in the same species. Autogamy occurs in singles of the Indian race and appears to be similar, cytologically, to that of American races. The details of the micronuclear behavior in conjugation parallel those of autogamy in singles. In fact, the conjugation process seems to be one of double autogamy (cytogamy), rather than of reciprocal gametic interchange. Paroral cones, often of fair size, are formed but breakdown of the cones to permit micronuclear passage has not been observed. In conjugation there are the usual three pregamic divisions; the first shows four characteristic crescents. The resulting nuclei may all participate in the second division. Fertilization occurs in the paroral cone area. Frequently, separation of the conjugants takes place immediately after the first division of the synkaryon. The old macronucleus undergoes very little change prior to the last postzygotic micronuclear division in the ex-conjugant, when it goes into a skein condition. Four macronuclear and four micronuclear anlagen are formed in the ex-conjugants at the completion of reorganization. On occasion giant individuals of P. polycaryum were observed to have ingested numbers of Tetrahymena pyriformis. The presence of an unidentified rod-like organism in the cytoplasm of the paramecia (non-conjugating) was detected in one collection from Bangalore, India.

Notizen: SYNOPSIS. The effects of some environmental influences on the cycle of Trypanosoma diemyctyli in Triturus v. viridescens are described. Bleeding of the host produced a reduction in the number of trypanosomes but did not affect their growth rate. The temperature at which the host was maintained affected the cycle of the trypanosomes. The length of the post-inoculation latent stage increased from 24 hours at 25°C. to an indefinitely long time at 5°C. The trypanosomes were found to be dimorphic. Adult parasites of the short form had a range of 45–75 μ and those of the long form of 76–116 μ. Growth rate of the trypanosomes was inhibited or greatly retarded at temperatures of 10°C. or lower and was greatest at 25°C. The size attained by the parasites and the number of parasites were greatest at 15°C. At this temperature the infection was pathogenic and the dimorphic parasites were in their long form. At the higher temperatures (20–25°C.) the infection was non-pathogenic with the trypanosomes in their short form.The infection is primarily one of adult newts. Experiments indicated that the larvae were resistant to the trypanosomes at all temperatures while the red efts were not. The latter are usually free from the trypanosomes because they are not exposed to them. Attempts to infect other newts and to locate any cryptic stages by the injection of blood and tissues from infected newts gave negative results.Starvation, sodium salicylate, and treatments used to control fungus infection of the newts had no detectable effects on the trypanosomes.

Notizen: SYNOPSIS. A comparative study of five species of Tetrahymena, including thirteen strains, was made to ascertain their ability to act as facultative parasites. A variety of experimental hosts, including both vertebrates and invertebrates, were inoculated with axenic cultures of protozoa. Infections were numerous in both larval and adult insects. Tissues of living vertebrates were invaded by one species of Tetrahymena through artificially produced wounds.

Notizen: SYNOPSIS. Unabsorbed, complement-inactivated antisera produced in rabbits were used in an immobilization system to study the serology of 31 strains of Tetrahymena pyriformis grown in axenic cultures at 26°C. Fourteen serological “groups” were found: 1. “H”: H, E, S, GC, L3, W, T, GHH, G1-R and sublines W-P and T-P; 2. “PR”: PR; 3. “GL”: GL; 4. “LR”: LR; 5. “L1”: L1 and L2; 6. “GP”: GP and Ch-S; 7. “WH”: WH6, WH14 and WH52; 8. “N”: N and HS; 9. “Y”: Y and TC; 10. “AA”: AA1, AA2 and AA4; 11. “F”: F and BF; 12. “Gf-J”: Gf-J; 13. “EZ”: EZ; 14. “Lava”: Lava. Not all of these “groups” were completely distinct; weak or variable cross-reactions occurring for particular cultures and antisera during the course of several years of observation suggested a relationship in terms of serotype potentialities, for strains in groups 1 and 2, and in groups 2, 3, 4, 5, and 6. Non-reciprocal cross-reactions are tentatively explained in terms of population fluctuations of serotype within particular cultures; several other suggested explanations remain possible. On the whole, however, the strains remained remarkably stable in dominant serotype.Observations on Tetrahymena in paralyzing antisera, with respect to the extrusion of a gelatinous exudate, in general confirmed previous observations by others. “Chain” formation was noted upon recovery, under conditions suggesting that the chains do not always derive entirely from incomplete cytokinesis of dividing organisms but that at least sometimes an aggregation of separate individuals is also involved. Synchronized division was observed for recovering organisms. A gelatinous material was obtained by centrifugation of a large number of individuals; this material provided a degree of protection to the organisms against antiserum effects while other colloidal materials did not, but the protective effects proved nonspecific in the sense that they were not confined to particular strain-antiserum combinations.

Notizen: SYNOPSIS. A rapid quantitative method for measuring trypanostatic activity by means of the nonpathogenic flagellate Herpetomonas culicidarum is described. Of the known trypanocidal agents tested, pentamidine was the most active; stilbamidine and propamidine somewhat less active. H. culicidarum is more resistant to these agents than are some pathogenic hemoflagellates. Two new antifungal antibiotics, nystatin and heptamycin (a candicidin-like antibiotic), had powerful trypanostatic activity in vitro. The potential trypanostatic activity of antifungal agents is noted.

Notizen: SYNOPSIS. Approximately fifty % of Natrix piscator from the vicinity of Bombay showed a haemogregarine in the peripheral blood. Schizogonic stages were found in great abundance in the lung capillaries, and occasionally in other internal organs. No parasites could be demonstrated in trombiculid mites of the genus Schongastia fed on infected snakes. Various developmental stages were found in the leech, Hirudinaria granulosa allowed to feed on infected Natrix piscator. The haemogregarine was originally described from this host in Ceylon on the basis of blood stages only and was named Haemogregarina mirabilis. Although the parasite exhibits several of the characters diagnostic of the schizogonic stages of the genus Hepatozoon, it is advisable for the present to retain it in the genus Haemogregarina.

Notizen: SYNOPSIS. A new species of a freshwater reticulate dinoflagellate, Woloszynskia limnetica, is described. The membrane structure and the shape of the membrane plates change during cell development. The rod-shaped mitochondria found among the membrane plates disappear in the adult cells; they constitute a center from which starch grains develop. Mitochondria also occur free in the endoplasm. Different physiological activities appear to be performed by morphologically identical chondriosomes. The stigma changes in different phases of the life cycle. The physicochemical properties of the ectoplasm govern the formation of specific structures of the membrane plates, which in turn determine the taxonomic position.

Notizen: SYNOPSIS. Pseudomicrothorax dubius, a rather rare protozoon assigned by Kahl to the trichostome order of ciliates, has been found and positively identified for the first time in America, and its morphology and morphogenesis have been studied in detail with the aid of modern techniques. The Chatton-Lwoff silver impregnation method is considered indispensable in acquiring an understanding of the ciliate's infraciliature: both its anatomy in the mature vegetative animal and its activities during the morphogenetics of binary fission.Stomatogenesis is of a complex type, considered here as “semi-autonomous” in nature, although a single, true stomatogenous meridian also is involved. Details of this explicit morphogenetic phenomenon are offered.The presence of a true zone of three adoral membranelles, never before recognized with any accuracy in this ciliate, a buccal cavity and associated structures, and the mode of stomatogenesis have led the writers to propose transfer of the genus Pseudomicrothorax from the Trichostomatida to the order Hymenostomatida.

Notizen: SYNOPSIS. Studies of the body ciliature of Balantidium coli and B. caviae (?) after Breslau's opal-blue and Klein's silver nitrate techniques revealed a preoral-dorsal suture area where some of the ciliary rows fail to reach the peristomial margin. The incomplete kineties ranged up to a dozen in number and were variable in arrangement. In a count of 100 specimens of B. caviae (?) the incomplete kineties were at the right of the suture in 39, at the left in 24 and on both sides of the suture line in 37. At the posterior end not many kineties reach the pole but no sutural pattern was seen in that region. Scattered irregularities in the ciliary rows were sometimes seen.Studies of the oral region tend to confirm the view of Fauré-Fremiet that the peristomial ciliature consists of short rows of cilia which are continuations of the anterior body kineties. Membranelles were not found. Thus, some species of Balantidium, at least, show affinities with the Holotricha in agreement with Nie and Fauré-Fremiet.Fission commonly produces two equal-sized daughters but many cases of unequal division were observed. In both these species conjugants are much smaller than vegetative animals and two preconjugant divisions are indicated, the first of which may be unequal.During the early stages of fission, the anterior ends of the kineties of the posterior daughter change direction, becoming oblique in the fission zone. In this region the kinetosomes multiply; possibly some of the kineties also divide but evidence for this is incomplete. No evidence of reorganization at the anterior end of the anterior daughter was seen.Attempts to infect hamsters with B. coli and B. caviae (?) failed. No parasites were found in two collared peccaries repeatedly examined.

Notizen: SYNOPSIS. Purification by migration on solid agar plates was studied with a small soil amoeba, Acanthamoeba sp., and a large fresh-water amoeba, Amoeba proteus. Purification seems accomplished largely by two mechanisms: egestion and attrition of contaminating organisms. Digestion may also play a role but probably is less important. The migration method is applicable to motile forms of the two amoebae which differ greatly in volume and motility. Therefore the method may be of potential value in purifying many species. Modifications which should extend the usefulness of the method are considered.

Notizen: SYNOPSIS. The gametes of Trichonympha grandis fuse quite differently from those of all the other species of Trichonympha in Cryptocercus; fusion is partial and temporary instead of complete and permanent as in other species. In this species, as in the others, fusion brings about the disintegration of all the extranuclear organelles of the male gamete, but none of those of the female; these persist to become the organelles of the zygote. Gametic union accomplishes two things: loss of extranuclear organelles of male and fusion of pronuclei. Unlike that of the other species of Trichonympha, the cytoplasm of the male gamete of T. grandis contributes slightly, if at all, to the formation of the zygote.

Notizen: SYNOPSIS. A new species of Hepatocystis (H. hippopotami) is described from the blood and liver of a Rhodesian hippopotamus (Hippopotamus amphibius). Its relationship with other members of the genus is briefly discussed.

Notizen: SYNOPSIS. The role of eleven different types of achromatic figures in chromosomal movement of Barbulanympha is analyzed. When only one pole is present, no chromosomes are ever connected with it, and hence they do not move. The chromosomes go through their usual life cycle including pairing, but remain in the parent nucleus, which, of course, does not divide. When two poles are present with only one pole near the nucleus, the poles, which are the distal ends of the elongate centrioles, do not cooperate in the formation of a central spindle and the chromosomal behavior is just as if there were only one pole—no movement. The same is true when more than two poles are present with only one near the nucleus.Unless a central spindle is present, movement of chromosomes never occurs. However, when many central spindles are present, sister chromosomes may separate and move to poles which are not directly connected by a central spindle. In other words, sisters may separate without moving along a central spindle.In binucleate cells with one central spindle the chromosomes of one nucleus move to the poles, but those of the other do not. Movement always occurs in the nucleus that has its nuclear membrane depressed by the central spindle. When two or more central spindles are present, the chromosomes of both nuclei may move to the poles.

Notizen: SYNOPSIS. Euplotes eurystomus Wrzesniowski was cultured on bacterial media with Tetrahymena pyriformis serving as the food organism. Animals were injured with various types of operations using the Chambers' micromanipulator. These animals were followed during the course of their regeneration using various nuclear stains, silver impregnation techniques and vital staining methods. It was found that two cirral fields arose as a result of injury removing one or more of the locomotor organelles and that the posterior field was soon resorbed, while the anterior one replaced all of the old cirri of the regenerating animal. In addition, in response to this sort of injury, complete nuclear reorganization took place. Animals which were injured in a manner not affecting the locomotor organelles directly, responded by proliferating a fine network in the area of injury. This network seemed to reinforce the injured area and persisted until the next binary fission of the animal. No nuclear reorganization took place in these cases.

Notizen: SYNOPSIS. The leech, Erpobdella sp., is a suitable invertebrate host for Trypanosoma ambystomae. The developmental cycle involves a mononucleate, rounded body derived from the bloodstream form; this body then transforms into a large plump crithidia. Subsequent divisions yield medium crithidia, small crithidia, and ultimately, metacyclic trypanosomes.

Notizen: SYNOPSIS. California ground squirrels (Citellus beecheyi) were found to be infected with trypa-nosomes whose most striking morphological features are an unusually large kinetoplast and a long, tapering posterior end. The total length is 25.2 μ, and body length is 18.0 μ. This “lewisi”-type species is compared with other trypanosomes reported from American ground squirrels, but a specific diagnosis is not made because the life cycle has not been observed and because morphological features of trypanosomes are known to vary widely under differing environmental conditions.

Notizen: SYNOPSIS. The basal apparatus of the flagella and kinetoplast in Leishmania donovani have been studied with the electron microscope. The flagellar fibrils extend into the body of the protozoan to form the kinetosome. At the point of origin of the flagellum, the pellicle invaginates to form a kinetosomal vacuole around the kinetosome. The kinetoplast is formed by a transversely elongated banded structure, surrounded at some distance by a double layered kinetoplast membrane. There is no apparent connection between the kinetosome and the kinetoplast.

Notizen: SYNOPSIS. Starvation of Isotricha prostoma for 72–96 hours decreased the cellular amylopectin granules and facilitated the microscopic search for bacterial feeding. I. prostoma selected and ingested only certain rods from among many types of rumen bacteria. In order to isolate the bacteria important as a food source for Isotricha, the starved protozoa were allowed to feed on mixed rumen bacteria, washed, and the crushed protozoan contents quickly cultured for bacteria. Several strains of bacteria were isolated in pure culture. Three of the rod strains isolated were rapidly ingested by I. prostoma when fed to the ciliate. In a monobacterial culture I. prostoma divided once before succumbing.

Notizen: SYNOPSIS. Cultures of Trypanosoma theileri were obtained at 36° and at 37.5°C. in a blood-lysate medium inoculated with blood from three dairy cows showing subnormal milk production. The organisms were first seen after 4 days in the first subculture, reached a maximum number of about 500,000 per ml. on the 4th day of the second subculture, and attained about this same number on the 4th day of subsequent transfers. Crithidial forms predominated but trypanosomes of the blood-stream type were also numerous. Cultures were not obtained from cows with normal milk production. The infected cows, although free from helminth parasites, showed a marked eosinophilia.

Notizen: SYNOPSIS. A new species of Paramecium, P. jenningsi, n. sp., from South India, is described. It is like P. aurelia except that nuclei are larger, the cell size is somewhat larger, and the macronuclear anlagen (“placentae”) have long-persisting chromatinic centers.

Notizen: SYNOPSIS. The nutritional requirements of 3 isolates of Prymnesium parvum (2 Israeli, 1 Scottish) included vitamin B12 and thiamine. For comparison, 2 other brackish chrysomonads were studied: Monochrysis lutheri isolated by Droop in Scotland and Isochrysis galbana purified by McLaughlin from a culture obtained from the Plymouth laboratory.The isolates of Prymnesium parvum and Isochrysis galbana had a molecular B12 specificity like Ochromonas malhamensis: no response to Factor B, pseudovitamin B12, Factor A or Factor H. M. lutheri, in contrast, responded to pseudovitamin B12, Factor H, and Factor A.Thiamine was essential; 1.0 μg.% allowed full growth of P. parvum. The NaCl concentration for good growth was 0.3–5.0%; growth was possible from 6–12%. Dark growth was not achieved.Ammonia, as suggested from its use in suppressing outbreaks of P. parvum, was sharply inhibitory, less so at high concentrations of NaCl or at acid pH.Nitrate, ammonia, arginine, asparagine, methionine, histidine, alanine, glycine, serine, proline, leucine, isoleucine, tyrosine, aspartic and glutamic acids, acetylurea, and creatine served as nitrogen sources in both acid and alkaline media.The phosphate requirement of P. parvum and M. lutheri and Isochrysis galbana was satisfied by inorganic phosphate, commercial glycerophosphate, yeast adenylic acid, cytidylic acid, monoethyl phosphate, and riboflavin monophosphate.Laboratory cultures in defined media of the isolates of P. parvum were toxigenic to Lebistes and Gambusia. Culture fluids from alkaline media were more toxic than those from acid media, as previously noted in Israel.Culture media suitable for production of large quantities of these organisms were developed.

Notizen: SYNOPSIS. Certain aspects of the metabolism of a Trichomonas batrachorum-type flagellate from the cecum of swine were studied. This trichomonad (1) oxidized glucose, mannose, maltose, sucrose, and inulin, (2) was incapable of oxidizing Krebs' cycle intermediates, (3) possessed peroxide-splitting capabilities, (4) was inhibited by only iodoacetate and arsenite, and (5) formed acid(s) aerobically. Although there was no effect on oxygen uptake, pyruvate and lactate increased the anaerobic evolution of gas(es). In addition to CO2, other gas, not absorbed by KOH, was produced anaerobically.Compared with other porcine trichomonads, the metabolism of this small trichomonad resembles most closely that of the large cecal trichomonad, T. suis. However, the smaller trichomonad had a generally lower respiratory rate, a slightly lower optimal pH, and failed to oxidize fructose, galactose, lactose, raffinose, and trehalose.

Notizen: SYNOPSIS. The “dry” silver method is redescribed with special attention to the possible difficulties encountered in its use. This method first revealed the silverline or neuroformative system of the ciliates, and is considered the best method for the demonstration of this structure. The valuable results obtainable with this technique are pointed out and illustrated with appropriate photomicrographs.

Notizen: SYNOPSIS. It has been assumed by others that green euglenas and derived bleached forms are physiologically equivalent except for chlorophyll and plastids. Some workers, however, have remarked upon differences which might depend on the mode of bleaching.Several hitherto undescribed chlorotic substrains of E. gracilis var. bacillaris were examined for pigment alteration, growth under a variety of conditions, and ability to withstand high temperature. These studies indicated physiological variation in the different chlorotic substrains. Although all were apparently chlorophyll-less and aplastidic, only one seemed completely achromatic. The carotenoid content of others varied. Metabolic changes manifested by altered pigmentation may reflect enzymatic variation caused by the chlorosis-inducing agents.

Notizen: SYNOPSIS. Thin sections of Amoeba proteus, fixed in osmium tetroxide and embedded in methacrylate, were examined in the electron microscope. The fine structure of various protoplasmic components is described. The plasmalemma, or cell membrane, varies in thickness and structure. These variations may be due to variations in physiological state, or they may be due to differences in preparation. Along its cytoplasmic edge is always present a definite line approximately 0.01 to 0.02 μ thick. The mitochondria, or beta granules, exhibit a structure similar to that of the mitochondria of several other protozoa and comparable to that of the mitochondria of other animals. In definite association with the membrane of the food vacuole are dense, rounded particles which in size are below the limit of resolution of the light microscope. Such dense particles are much less frequently present in the hyaloplasm and in association with the plasmalemma. A possible relationship to the neutral red granules associated with food vacuoles of Paramecium is suggested. The contractile vacuole possesses a thin membrane surrounded by a much thicker circum-vacuolar zone of irregular strands which may form a three-dimensional network around the membrane. This may represent the contractile element of the vacuole. A single layer of mitochondria is closely apposed to the circum-vacuolar zone. Many small vacuoles and irregular vesicles are present throughout the cytoplasm. At times there occur groups of small, thin-walled vesicles, which may correspond to an endoplasmic reticulum. The nuclear envelope consists of a thick inner porous layer and a thinner outer layer that is continuous yet is marked by the presence of numerous small annuli, each apparently surrounding a pore. In its structure, this outer layer appears to correspond to the entire nuclear envelope of many other cell forms.

Notizen: SYNOPSIS. Irradiation of Stentor coeruleus with Xray doses of 150–300 kr inhibited growth in size and fission. The irradiation also led to the development of structural abnormalities, which appeared about a day after irradiation. The inhibition of growth and fission was independent of the oxygen concentration during irradiation, but the abnormalities were produced at lower doses in nitrogen than in air. Regeneration of parts removed by cutting occurred even at the highest doses at essentially normal rate even during the period when over-all growth was completely inhibited. The conclusion is drawn that delay in fission by radiation is a secondary consequence of inhibition of growth and not a consequence of blocks in the specific morphogenetic processes required for division.

Notizen: SYNOPSIS. A description is given of the formation of an unusual type of achromatic figure by two very long, narrow centrioles. The unique manner in which this structure functions in chromosomal movement is explained.

Notizen: SYNOPSIS. Crosses between serine requiring and non-requiring clones from natural habitats give rise to progeny that are numerically equally distributed between the two categories. Most of the progeny from crosses between two serine requiring parental clones require serine with a few segregating out that do not need the amino acid. These data indicate that the gene or genes controlling the serine non-requirement are recessive to the wild type which requires serine. Growth of the F1 progeny was highly variable. Some clones failed to survive on serine deficient media and were therefore tentatively assigned the genotype +/+. The remaining clones were of two classes: one grew slowly on serine deficient media and was given the genotype of the heterozygote, +/s; the other grew without serine, hence was given the double recessive genotype, s/s. The F2 progeny from matings of s/s and s/s need no serine whereas the cross of +/s and s/s gave equal numbers of serine requiring and serine non-requiring progeny. The cross of two heterozygotes, +/s and +/s, yield progeny approximating the 3:1 ratio in favor of serine requiring clones. Crosses at the F3 level produced non-viable offspring in all cases except one. Progeny from this cross with the genotype s/s were mated giving rise to F4 progeny all of which grew without serine. The data support an outbreeding economy for this organism with selection in favor of the heterozygote. Although the data seem to favor a single-gene hypothysis, suppressor genes may be involved. With selection favoring the heterzygote, distorted genetic ratios make the data difficult to analyze.

Notizen: SYNOPSIS. Intracardial inoculation of 1–10 million L. donovani in 0.1 ml. of ground spleen suspension from an infected animal (hamster) results in a uniform rise of parasite numbers in the untreated animal over the first 8 days after the inoculation. This rise is highly consistent from experiment to experiment.Treatment is accomplished by parenteral injection of a compound for 6 successive days in this time interval, starting 24 hours after inoculation.No known active compound in proper dosage (sodium stibogluconate, pentamidine, fuadin) has failed to show a significant suppression of the expected rise in parasite numbers. No known inactive compound has had any effect on the course of the infection.The dosage-response curve for the active compounds suggests that the method is a sensitive one. Since it takes only 8 days to complete, it is economical as well.

Notizen: SYNOPSIS. It has been shown that the output of the contractile vacuole of Crithidia fasciculata increases as the concentration of solute in the external solution decreases when NaCl is the solute. The increase in output is the result of increased rate of growth as well as increased maximum size, the latter being more important in the range 0.1M–0.01M. Solutions of penta-erythritol produce the same effects as isosmolar solutions of NaCl. Body volume is not maintained constant but increases less than two-fold between 0.1M and 0.0001M. The isotonic concentration of NaCl is estimated as 0.12M. It is not possible to demonstrate any effect of concentration of the external environment on the endogenous rate of oxygen consumption. A linear relationship between output and calculated osmotic gradient across the cell membrane has been shown in the concentration range 0.1M–0.01M. Absence of this relationship, and failure of body volume to increase as predicted, in solutions more dilute than 0.01M are interpreted as indications that other processes probably become predominant in these solutions. It is concluded that the contractile vacuole of this flagellate is incapable of maintaining absolute constancy of internal osmotic pressure and body volume but prevents much of the change expected on physical grounds.

Notizen: SYNOPSIS. The rather rarely found holotrichous ciliate Pseudomicrothorax dubius, generally considered in the most authoritative literature to be a member of the order Trichostomatida, more likely belongs in the Hymenostomatida. Its curious combination of trans-ordinal characteristics, however, makes difficult exact systematic allocation of it and of the congeneric species P. agilis. The provocative morphological features include: a gymnostome-like cytopharyngeal “basket”; a tetrahymenal buccal apparatus, with membranelles comparable with those of primitive hymenostomes; an advanced semi-autonomous type of stomatogenesis; and sensory bristles, flattened rigid form, and restricted ciliature reminiscent of certain spirotrichs. Brief discussion is presented concerning the influence of modern ideas of ciliate classification upon what is considered the proper taxonomic position of the genus.

Notizen: SYNOPSIS. A new fresh water species of Actinosphaerium is described, the fourth member of the genus. Some of the more significant of its diagnostic traits are: 1) the Actinophrys-like nuclei with peripheral nucleolar granules and without central rosette-shaped nucleoli, 2) the occurrence of some nuclei in the ecto-endoplasmic border and the insertion of axial filaments on them, and 3) the low ratio of endoplasm to ectoplasm.

Notizen: SYNOPSIS. In cultures of the marine dinoflagellate Gonyaulax polyedra grown with alternating light and dark periods of 12 hours each, at least 85% of all cell divisions which occur in a day take place during a 5-hour period spanning the end of the dark period and the beginning of the light period. A very distinct maximum in the number of recently divided cells occurs at about the time the light period begins.This diurnal periodicity in cell division is lost after 4 to 6 days in continuous bright light, but will persist for at least 14 days in continuous dim light. The period of approximately 24 hours under constant conditions is only slightly altered by varying light intensity and temperature, both of which factors are known to affect markedly the generation time. The time at which cell division occurs is therefore postulated to be controlled by some sort of rhythmic or clock mechanism.Similarities between the cell division rhythm and the endogenous rhythm of luminescence in this organism are discussed. The occurrence of a glow, or steady light emission of low intensity, at about the time of cell division, is described, and it is suggested that this glow may result from cellular changes accompanying certain stages of cell division.

Notizen: SYNOPSIS. The photographs illustrate male and female gametes before fertilization, several progressive stages in the entrance of the male gamete into the cytoplasm of the female, cytoplasmic fusion of gametes, loss of extranuclear organelles of male gamete, retention of extranuclear organelles of female gamete, movement of pronucleus of male gamete to that of female, progressive stages in fusion of pronuclei, and the formation of the zygote which possesses the extranuclear organelles of the female gamete. Some abortive attempts at fertilization, resulting from failure of gametes to differentiate, are shown.

Notizen: SYNOPSIS. Detailed directions are given for the preparation of a simplified assay medium and of natural materials for assay of pteridines with Crithidia fasciculata. Unconjugated pteridines in natural materials which also contain conjugated pteridines (folic and folinic acids) can be assayed by destroying the conjugated pteridines with acid hydrolysis, which does not appreciably alter Crithidia-active unconjugated pteridines. The widespread occurrence of unconjugated pteridines and their significance in such processes as photoreception are discussed.

Notizen: SYNOPSIS. Photokinesis or the non-directed rate of swimming of Euglena gracilis for various light intensities was studied. The rate of swimming in white light was found to increase with light intensity until it reaches 0.16 mm./sec. at a saturation of 40 ft. candles, and then decreased with increasing light intensities. Polarized light appeared to be more effective (0.18 mm./sec. at 13 ft. candles) than non-polarized light.The action spectrum for photokinesis showed two peaks, a major one near 465 mμ, and another in the neighborhood of 630 mμ, having the values of 0.18 mm./sec. and 0.16 mm./sec. respectively at an intensity of 4 ft. candles.The action spectrum for phototaxis, or directed orientation, had a peak near 420 mμ and showed a maximum near 490 mμ. Both dark-grown and dark-adapted Euglena showed spectral peaks similar to those of the light-grown cells. For polarized light, the action spectrum had two additional peaks at 468 mμ and 508 mμ. The polarized light effect may indicate more than one light-absorbing pigment within the “eye spot” or that other pigments within Euglena were absorbing.

Notizen: SYNOPSIS. Four new species of Eimeria are described from small mammals in Liberia. These are: E. levinei, sp. nov. from a free-tailed bat, E. firestonei, sp. nov., and E. milleri, sp. nov., from a shrew, and E. putevelata, sp. nov., from a striped grass mouse.

Notizen: SYNOPSIS. A new species of Stentor is described, a fresh water form, medium sized, with cerulean blue pigment, and characterized by retractable feeding organelles.

Notizen: SYNOPSIS. Coprozoic protozoa from elk, bison, bear, moose, coyote, marmot, cattle, horse, sheep and man were kept in feces at 4° C. for 2–6 months. During that time in most of the samples there developed the flagellates Cercomonas sp., Copromonas ruminantium and Monas communis; the amoebae Vahlkampfia sp. and Sappinia diploidea, and ciliates of the Nyctotherus type, and an unidentified smaller species. There was a correlation between numbers of protozoa and bacteria. The same species of protozoa in soil or in soil mixed with boiled feces failed to live. Coprozoic protozoa may require certain essential metabolites from bacteria as do true parasites. The wide variation in appearance of cysts made it practically impossible to identify the protozoa with certainty in that stage. Reliance had to be on motile forms which readily developed in the cold cultures.

Notizen: The attention of everyone has already been drawn to the part which accident reports must play (Geophysical Prospecting, March, 1957, PP- 1 to 8). We intend to show here, with supporting examples, that the systematic analysis of the causes, does allow one to obtain practical conclusions.To begin with, it is advisable to widen the notion of geophysical accident as much as possible. This being done, about 200 reports distributed over a long period and a sufficient number of parties, are dealt with. The collected reports are sufficiently numerous to draw conclusions in a general way bearing on the headings: drilling, transport, outbreaks of fire, explosives, falls, stings, shocks, miscellaneous causes.All the quoted figures are referred to the number of accidents reported. Action must be taken to encourage european geophysicists to study accident reports and to analyse the causes. This may be done in such a way that secret information, such as whereabouts of their personnel, is not disclosed.Efforts to promote “Security” must in the first place bear on the quest for the causes, the definitions of ‘accident’ and of ‘geophysicist’ being taken at their widest possible meaning.

Notizen: Seismic model experiments are described in which long strips of plexiglass were used as models. One end of the strip was sawn off at an oblique angle and, at the opposite end, the strip was excited by means of a barium titanate transducer. The experiments showed that, if the width of the strip was sufficiently small, an anomalous reflection against the oblique end occurred which travelled in the longitudinal direction of the strip. This anomalous reflection did not occur when the width of the strip was large. These results are explained on the basis of Fresnel's theory. It is inferred that, in the subsurface, refracted waves may be reflected against fault planes without the law of reflection being satisfied, provided that the refracted wave is propagated in a sufficiently thin high velocity layer.

Notizen: Changes of shape of seismic waves provide information on the properties of the material in which the waves propagate. Ricker (1953) has attempted to explain the changes of shape on the basis of a simple viscoelastic theory. His conclusions are at variance with those of others who find a dependence of the attenuation on frequency which could be explained only by a much more complicated linear theory or by nonlinear theories.To provide a basis for discussion, the essentials of the theory of viscoelasticity are briefly reviewed. If a relaxation spectrum, rather than one or very few relaxation times, is admitted, a great variety of experimental results can be described by the linear theory of viscoelasticity. A linear theory is indicated when no obvious violations of the principle of superposition occur.Ricker's theory is presented with some modifications which allow for a finite duration of the initial pulse and for the approximate character of his basic assumptions. There do not appear to be serious discrepancies between his theory and his experimental results. Some of the objections to his theory can be met by assuming a finite duration of the initial pulse. However, more direct measurements made under similar circumstances by McDonal et al. (1958) at the same location lead to a conclusion on the nature of the material not in accordance with Ricker's. This casts doubt on the sensitivity of his method.Laboratory measurements usually yield results which are not explainable in terms of simple viscoelastic models. Whether a linear theory with a relaxation spectrum or a nonlinear theory should apply depends much on the experimental conditions. We must also consider the possibility of nonlinear mechanisms which are active at small amplitudes. No stand is taken in this controversy, but it is pointed out that the question linear or nonlinear could be decided experimentally without considering the details of the theories.

Notizen: A method of refraction computing is described which establishes the two points of incidence at the surface of the ray-paths from any point on the refractor when observed from opposing directions. The distance between these points is used to determine the radius and the centre of a circle to which the refractor must be tangential. The matching of forward and reverse data is intrinsic in the method so that the resulting profile is automatically positioned in depth. It is shown that if the effects of dip are neglected, errors are introduced in the derived radius and also in the position of the centre but these errors are shown to cancel each other almost exactly.

Notizen: The wells Parentis 10 and 12 which are located on the eastern edge of the Parentis anticline were found to be considerably lower at the top of the reservoir series than had been expected.Unfortunately the village of Parentis is located in this important zone and no more seismic results could be obtained which might help locate faults and give a better picture of the area. To help in our understanding of the area, we attempted to investigate the subsurface conditions surrounding the wells by shooting shaped charges or primacord in the well and recording the returning seismic energy along profiles located on the surface. Thus far, we have used this method in three wells: Parentis 10, Parentis 12 and Lugos 2.With the data given by a velocity survey in each well, time-distance curves have been calculated for several typical possibilities: horizontal layers, dipping layers and the effect of a fault. A comparison of the calculated and experimental curves shows anomalies which correspond to a change of the average velocity along the travel path, which can correspond to geological changes such as: a sudden change of dip, a fault or a thickening of the section.The anomalies have been studied on the different profiles from each well and a possible interpretation of the subsurface conditions has been given. The directions of the major accidents determined by this method are in general agreement with those found by the regular seismic shooting.

Notizen: The directional sensitivities of an array of geophones depend as much on the size of the array as on the directional sensitivities of the single geophones forming the array. In a former paper (Celminš 1956) the effect of the size of the array was investigated. In addition to this the influence of the directional sensitivities of the individual geophones on the sensitivities of an array of geophones is investigated here.In δ 2 some general formulae for the directional sensitivities are derived. In addition the directional sensitivities of a single geophone according to P- and S-waves are investigated (δ3 and δ4). In δ5 the'directional sensitivities for the most important cases of arrays of parallel geophones are computed. The results of the computation (shown in fig. 4 and 5) give an idea of the types of directional sensitivities which occur in the use of geophone arrays.

Notizen: A study has been made of the flowering requirements, for temperature and photoperiod, of a range of timothy strains, including American, British and Scandinavian material.All the strains tested are long-day in their photoperiodic responses, and there is no “winter requirement” for low temperature (0–5°C.) or short days before flowering. There is, however, an inhibitory effect of high temperature in the greenhouse on flower formation, lf the temperature is too high, no heads are produced, although photoperiod may be adequate. Instead elongated indeterminate shoots are formed which often become stoloniferous.The effect of high temperature varies with the strain, and appears to be related to the May temperature of the region of origin. Under greenhouse temperatures of 55–65°F. American and Canadian commercial strains show little inhibition of flowering, but many plants of the Scandinavian strains fail to produce heads. The British hay strains show intermediate heading behaviour, but only an occasional plant of the diploid S.50 formed heads under these conditions.

Notizen: Heading behaviour of eight strains of timothy was observed in the sowing and first harvest years, after sowing on a series of dates between March and August.All strains produced heads in the sowing year. Only a very few plants failed to head when sown between 18 March and 29 April. With subsequent sowing dates the proportion of heading plants progressively declined, most markedly in S.50 Phleum nodosum, least in the early-heading P. pratense strains. No heading occurred in the sowing year after the mid-August sowing.The environment to which the later sowings are exposed differs from that of the earlier sown lots in that (a) the initial temperatures and daylengths are higher and (b) the decline in daylength occurs earlier in their development. One or both of these factors must be responsible for failure of heading among plants of the later sowings.The sequence of heading dates among the strains in the sowing year differed considerably from that in the same plants after overwintering, suggesting the action of some factor other than photo-period in determining heading date in the sowing year.Variability in heading date within the strains was much greater in the sowing year than after overwintering, and increased with lateness of sowing.

Notizen: Experiments are described in which a study was made of the top growth, root weight, nodule number, and type of nodules of white clover growing in a grass sward in the field. Soil cores were taken and the clover root-system examined after removal of soil by washing.The most important factor governing the total number of nodules and the number of large (2 mm. or more in length) nodules under the sward was the amount of clover root-material present.Nitrogenous fertilisers and the return of dung and urine by grazing sheep reduced the amount of clover root-weight and consequently the number of nodules found under the pasture. 36 1b. of nitrogen applied in the early spring of 1956 had a beneficial effect on both clover top-growth and nodulation. 80–100 1b. of nitrogen per acre had no effect on the number of nodules per gram of root. However, the application of 200 1b. of nitrogen per acre caused a significant decrease in the number of large nodules per gram of root.The numbers of large nodules present reached a midsummer peak where nitrogen was not applied.During the autumn many nodules showed part green and part pink colouration or were completely green or brown, an indication of a decline in nitrogen-fixing ability. Decaying nodules increased considerably in number when the legume was being suppressed by nitrogen application and top growth was poor. The practical application of these results is discussed and methods of maximising the benefit from clover and fertiliser nitrogen are suggested.

Notizen: A trial is described which was designed to test the hypothesis that measurements taken of the leaf-plus-shoot length of spaced plants may give a good indication of dry-matter yield of strains of Dactylis glomerata, as determined by cutting and weighing the produce of sward plots.Two contrasting strains of Dactylis glomerata were used: the British S.143, and the German von Kamekes. The strains were established during 1955 both as spaced plants (10 plants per plot) and as pure swards, with six replications of each. The two methods of establishment formed the main treatments, occupying whole plots, and each plot was divided into four sub-plots each of which carried one of the combinations of the two strains with the following two management treatments: Treatment 1, cut at monthly intervals from 27 April to 23 August; Treatment 2, cut on 12 April and subsequently at the mean date of emergence of the inflorescence for each strain, followed by cutting at monthly intervals until the end of August.Spaced plants were measured before cutting by thrusting a measuring rod into the crown of the plant and measuring the leaf-plus-shoot length of one of the longer shoots. Produce cut from sward plots was weighed and sampled for dry-matter content.Results from the swards showed that von Kamekes produced more dry matter in early spring, but that subsequently the advantage passed to S.143.Significant positive correlations were obtained in early spring between the sward yields and leaf-plus-shoot measurements from spaced plants. Subsequently there was no agreement between the two methods, and some significant negative correlations were obtained.The data are discussed in relation to the physiological stages of development of the strains, which suggests that:〈list xml:id="l1" style="custom"〉(a) In the spring period the main factor contributing to yield was shoot elongation, with the majority of the tillers in the reproductive phase.(b) In summer the main factor was new tiller formation, with the majority of tillers in the vegetative phase.(c) In the early autumn neither factor was dominant and both contributed to yield.Attention is drawn to the danger of comparing yields from spaced plants with yields from swards where the management may influence the results obtained, and to the difficulty of assessing hay yields by means of height measurements of spaced plants.

Notizen: An experimental silo unit consisting of four silos, each capable of holding 1000 kg. fresh grass, is described. The silos are suspended from a weighing apparatus enabling weight recordings to be taken at all stages during ensilage. The weighing apparatus is sufficiently sensitive to record a change in weight in the silo and contents of 100 grams.

Notizen: Foggage grazing trials with beef-store cattle and in-calf dairy heifers during four successive winters in Aberdeenshire are described. Many of the animals received only very small quantities of supplementary fodders, but their performance was satisfactory in all cases. During the last two winters, silage and oat straw contributed 40–50% of total food dry-matter intake. It is suggested that this level of supplementary feeding would be satisfactory in practice.In a comparison of store-feeding systems, four in-wintered (housed) steers were 110 1b. per head heavier than their out-wintered monozygous twins at the end of the winter-feeding period. Live-weight differences averaged 27 1b. per head one month later and were negligible at the end of summer. From the results of a metabolism trial it was concluded that the spring weight-loss suffered by the housed cattle was due mainly to a reduction in the weight of gut contents.

Notizen: Yields were recorded from a potato crop grown in the first year following a grazing trial comparing four strains of white clover, previously described in this journal (2 & 3). The Kent clover strain, which was the most persistent and which had produced the greatest live-weight increase per acre, gave the highest yield of potatoes. The Dutch white clover, which had been the poorest in the grassland trial, gave the lowest yield of potatoes.A 2 × 2 × 2 N, P, K fertilizer design was superimposed in the form of split plots. Nitro-chalk at 5 cwt. per acre and muriate of potash at 2 cwt. per acre both caused significant reductions in yield, and this was thought to be due to the exceptionally high soil fertility status of the field. The fertilizer × clover interactions were non-significant, and contributed little towards an explanation of the fundamental basis of the soil fertility differences caused by these four clover strains.

Notizen: The vigour of perennial ryegrass and cocksfoot after spraying with the sodium salt of MCPA during establishment was estimated from their yields in small-plot cutting experiments on weedy land. Where the weed yields of control plots was of the order of a ton of air-dry matter an acre (mostly Spergula arvensis L.), spraying at up to 1·2 1b. acid equivalent an acre caused twofold to threefold increases in grass yields. The optimum time to spray perennial ryegrass was at the three- to four-leaf stage or 26 days after sowing; for cocksfoot, which appeared more susceptible to the herbicide, spraying at the tillering stage, or about 40 days after sowing, was best. Increasing the seed rates of ryegrass produced transitory increases in yields while decreasing weed yields. Increasing phosphate or nitrogen caused decreases in weed yields. Although the former gave a large increase in weed yield in the first cut this was offset by a large decrease in the second cut. There was an indication that the level of nitrogenous manuring affected the toxicity of the herbicide to the grasses.

Notizen: Book reviewed in this article:WHEELER, W. A. and HILL, D. D. Grassland seeds.

Notizen: As an introduction the various ray paths of a refraction wave, which is reflected at a fault, are discussed for the case of an arbitrary angle between the refracting horizon and the fault. Simple geometric considerations lead to the conclusion that the best chances for recording these pulses are encountered, if the angle between the refracting horizon and the fault is either 90° or the critical angle of refraction. In both cases identical travel times of the pulses are to be expected.The case of a fault perpendicular to the refracting horizon is considered in detail for dipping beds. Formulas for the shot point travel time curve and the time contour map are derived. Computed time contour maps show considerable differences between the direction of strike of the contour lines and the strike of the fault, as well as between the recorded apparent velocity and the true velocity of the refracting horizon. Finally, alignment charts and computing procedures are given by which the position of the fault and the velocity of the refracting horizon can be obtained from the recorded shot point travel times or the time contour map.

Notizen: It is not easy to record a seismic pulse at distances of interest to oil prospectors without there being reflected or refracted pulses superimposed on the direct arrival. Accordingly the record illustrated is considered worth publishing, although it was taken fortuitously during a normal survey and cannot claim to be a controlled experiment. A comparison with the filtered pulse to be expected from a theoretical Ricker-type wavelet is presented.

Notizen: In this paper a method of calculating synthetic seismograms from continuous velocity logs (CVL) is presented and described in detail.The seismic velocities on the CVL are frequently and rapidly changing. Therefore a seismic field-record consists of a great number of reflections with different sign and amplitude. The sum of all reflections forms the seismogram.The first part deals with some relations between the log, the reflection-layers, and the normal field-record, with special emphasis on the influence of the seismic amplifier.Then several assumptions are made for the construction of the synthetic seismograms. Finally some examples and applications are given.

Notizen: The Karroo of Madagascar is a thick continental deposit of sandstone with some shale, but no characteristic beds. Where it outcrops, velocities have been measured through bore hole surveys. It seems that they depend primarily on the age, but long refraction soundings show a progressive increase of the velocity with depth and a weak differentiation of the marker beds. These results may possibly be brought in accordance by discriminating between the present position and the deepest position of a bed through its geologic history. Thus we must admit very important erosions which, according to regional geologic data, seem possible. If we make the appropriate correction due to this distinction, all the velocity measurements fall near the curve proposed by Faust for an average shale and sand section.

Notizen: Some new formulae for the rapid estimation from the gravity field of the maximum possible depth to the top surface of gravitating bodies of positive mass are stated, discussed and proved.

Notizen: The shothole drilling industry has had new developments and its evolution is tied to several causes. First, more and more difficult and varied formations have to be drilled. Second, new procedures have to be used in desert regions recently open to prospecting. Finally, modifications of the seismic methods themselves (multiplication of the charges, shallow holes, etc.) lead the driller to use more economical and lighter tools. In this paper the following types of drilling equipment are described: the Mouton Delmag for spudding through pebbles and loose gravels; a mud mixing water truck and an extensible mast used for drilling multiple medium depth holes through caving sands; a compressed air-drill for regions where the water supply is practically nil; rock drills, such as a Wagon-Jack and the Warsop hammer, for multiple shallow holes in various formations.

Notizen: The receiving of seismic waves by multiple geophones (geophone-group) is described by a system of coupled differential equations considering only effective resistances. For so-called symmetrical connections of the geophone-group which are used in practice nearly in all cases, a method can be given for solving this system of differential equations. The solutions so derived are valid for seismic waves of any shape. The calculation takes into account the coupling of the geophones as well as the building-up transient oscillations.A suitable measure of superposition is defined, based on the energy transferred during the receiving of the seismic waves. By this means effects similar to interference are investigated which occur at the geophone-group. As a numerical example calculation is carried out for a geophone-group consisting of three geophones which is excited by impulse-shaped waves of the form of a damped sinusoidal oscillation. The occurring effect of superposition and its dependence on direction are discussed. In the appendix formulae are presented for investigation of further numerical examples.

Notizen: The Geophysical Journal of the Royal Astronomical Society, Volume 1, No -, March 1958. Published by the Royal Astronomical Society, Price $ 1, Annual Subscription $ 3. Grundlagen der Geoelektrik by A. P. Krajew. herausgegeben unter der Gesamtredaktion von Prof. Dr. Otto Meisser, VEB-Verlag Technik, Berlin, 1957, Price D.M. 28. Grundlagen für die Auswertung von magnetischen Anomalien (insbesondere Z-Kompo-nente)– (Fundamentals of the Interpretation of Magnetic Anomalies, Especially of the Vertical Component) by K. Köhler, Freiberger Forschungshefte C41 Geophysik, Akademie-Verlag, Berlin, 1958.

Notizen: Electronic recorders have been used for recording borehole logs since several years.Some difficulties are however experienced in recording more than two curves at the same time.An experimental 4 curves electronic recorder has been constructed using up to date miniaturized servomechanism components.A general description together with performance data is given; applications of the same construction principles to pen recorders with a greater number of curves and to photographic recorders are also discussed.

Notizen: The Kodur Manganese belt has been surveyed with a vertical magnetometer. It was generally observed that both high positive and negative anomalies were associated with some of the existing ore bodies. Other large manganese ore deposits gave little or no magnetic anomalies. Further it was observed that both types of manganese ore deposits giving rise to large and little magnetic anomalies, contained similar percentages of manganese and iron. In view of these discrepancies, an extensive study of the magnetic properties of these manganese ores was taken up. The results of these measurements showed that the susceptibilities of the manganese ore samples collected vary over a wide range.It was observed that the high susceptibilities are associated with samples containing manganmagnetite and vredenburgite, whereas samples rich in psilomelane and pyrolusite possess low susceptibilities. From the chemical analysis, normative values of manganmagnetite and vredenburgite–with a general formula of (Mn.Fe)3O4– were calculated and a linear relationship could be established between these normative values and susceptibilities.

Notizen: This paper deals with the second three years (April 1954 to March 1957) of a grazing-management trial in the form of a pilot farm. The whole area of 35.5 acres was run as a self-contained unit with the object of providing grazing for as long a period of the year as possible. A system of rotational grazing was used throughout with strip- and fold-grazing at certain seasons. Excess herbage was conserved as silage and hay and fed back to stock during the winter. Beef-type steers and ewes and lambs grazed the pastures, the saleable products being fat cattle, lambs and wool. Results are presented and discussed in relation to stock numbers, animal health, herbage production and botanical composition, fertilizer application and the levels of production achieved. Over-all average fertilizer dressings per acre for the three years were equivalent to 5 cwt. per acre nitro-chalk, 2 cwt. per acre superphosphate and 1 cwt. per acre muriate of potash. The outputs of utilised starch equivalent in 1954–5, 1955–6 and 1956–7 were 2970, 2850 and 2280 1b. per acre, respectively. On the basis of the six years' results it is concluded that high production can be achieved from a system where the object is an extended grazing season; that broadcast leys can be used for winter grazing and the botanical composition of the sward maintained; that self-fed silage can be a satisfactory feed for fattening cattle; that a grazing plan is a valuable guide to management; and that the pilot-farm method is of value for certain agronomic experiments.

Notizen: Utilised grass production on ten small farms in North County Dublin has been estimated using (A) the method adopted by the British Grassland Society Sub-Committee on the assessment and recording of the utilised output of grassland, and (B) a live-weight increase method using Woodman's figures.At the beginning of the grazing season all the grazing animals on each farm were weighed. At the same time the records for method A were begun. Altogether 169 animals and 12 sheep were weighed during March-April. Animals sold during the period of investigation were weighed, where possible.The results obtained using the two methods have been compared. Average percentage difference on ten observations was 11.3%, with a variation of ± 3.7%. On farms 1–5, where only mature stock were kept, the percentage difference was 9.9%± 2.2%. On farms 6–10, where animals of all categories were grazed, the percentage difference averaged 12.8%± 2.2%. In all cases the live-weight-increase method gave the higher estimated yield.The techniques used in the estimation of utilised grassland production are discussed. Total output varied between 26.5 cwt. and 9.0 cwt. of utilised S.E. per acre. The significance of the findings is discussed and the value of the methods used is considered.

Notizen: A leafy strain of timothy and of perennial ryegrass showed no significant reductions in seed yields following grazing at different dates from October to January, when extra nitrogen was applied.Spring and winter + spring grazing, together with extra nitrogen, significantly reduced the seed yield of S50 timothy for three successive harvest years.Perennial ryegrass S101 showed no reduction after spring or winter + spring grazing when defoliation was made not later than mid-April, but when grazing was delayed until May and drought occurred there was a significant reduction in seed yield.

Notizen: Messrs. A. W. Montgomerie and Sons of Lessnessock, Ayrshire, manage their grassland so as to encourage full development of white clover. The method is an adaptation of the system followed in New Zealand. The results are that production in terms of stock output is high, reaching a utilised starch equivalent of 23 cwt. per acre.

Notizen: The differences in soil fertility in a ley as a result of treatments applied for four years in a sheep-grazing trial were measured by growing crops of wheat and kale. The pasture treatments had been: control, dung, urine and dung plus urine, each combined with four levels of fertilizer nitrogen.Yields of winter wheat harvested in 1956 ranged from 27.1 to 38.6 cwt. per acre. Plots to which faeces had been allowed to return during the pasture phase outyielded (p 〈0.001) those from which it was withheld. Urine was relatively ineffective except in combination with nitrogen. In the absence of animal returns, nitrogenous fertilizer depressed grain and straw yields. A top-dressing of K applied to the wheat in spring as a sub-treatment had no significant effect. The percentages of N and K in the grain were unaffected by the former pasture treatments, or by the K top-dressing.A subsidiary small-plot experiment in which the above pasture treatments had been combined with P and K, each at two levels, was cropped with marrow-stem kale. In general, N applied to the pasture increased kale yields except where dung and urine had been withheld. Neither P nor K had a significant effect, except when combined. The leaf/stem ratio of the kale was reduced by applied N and by P (both p 〈0.05).The pasture/arable-crop relationship is considered.

Notizen: A series of six trials with eight strains of perennial ryegrass at two levels of manuring has now been completed. Results indicate that a moderate application of artificial manures gives a high degree of control over Gloeotinia temulenta infection. The degree of infection may be influenced by climatic conditions. Each strain has a definite inherent susceptibility or resistance to the disease. The most resistant strains are the commercial strains Irish Commercial and Devon Eaver; S24 is the most susceptible, followed by New Zealand Certified Mother Seed.