Showing papers in "Proceedings of The Royal Society B: Biological Sciences in 1911"

The intrinsic factors in the act of progression in the mammal

Abstract: Whilst the act of progression is being performed, the several limbs exhibit rhythmic movements of flexion and of extension. When any limb is in contact with the ground, it extends, and thus serves to propel the animal forwards. At the end of this act the limb is lifted from the ground by a movement of flexion, is carried forward, and finally is again placed upon the ground to repeat the cycle. During these phasic acts the dynamic balance of the neural centres is disturbed by two different kinds of peripheral stimuli. In the first place, the discontinuous contact with the ground, and the synchronous distortion of the skin of the foot—determined by the weight of the animal then carried in part by that limb—produce changes in the activity of exteroceptive end-organs therein embedded, and discontinuous augmentations and diminutions of the stimuli originated in them.

Electrical effects accompanying the decomposition of organic compounds

Abstract: The results of recent researches in electro-physiology have familiarised us with the view that any physiological process accompanied by chemical changes involves an associated electrical change. Haacke and Klein have shown that electrical currents in plants are essentially a manifestation of vital phenomena, and that differences in electric potential are connected both with respiration and carbon assimilation. Waller's investigations have also shown that the excitation of living vegetable protoplasm gives electrical response no less than that of animal protoplasm. He has demonstrated that leaves in a condition of active metabolism give an instant electrical response to the influence of sunlight, which was modified under conditions affecting protoplasmic activity. Apparently almost immediately upon the perception of the stimulus of light, electrical energy begins to be absorbed in the process of photosynthesis. Waller approaches very suggestively the existence of two opposing forces in the presence of analytic and synthetic processes, and recognises that the function of assimilation and respiration might be mutually antagonistic as regards visible electric effects. His conception that "the product of dissociation …. gives current from the focus of dissociation, whereas a product of association, during its formation, gives rise to a current in the opposite direction," is of great interest. The line of enquiry now followed lies in the direction only of dissociation, and is a study of electrical effects accompanying fermentation or putrefaction under the influence of micro-organisms such as Saccharomyces or bacteria. The special physiological character of fungi or bacteria demands the disintegration of organic compounds as a necessary source of energy, and where there has been absorption of energy in a synthetic process one must look for its liberation when the change is of an analytic nature. The evolution of caloric energy during fermentation or putrefaction is commonly recognised, and that electrical energy is also liberated during these processes is a conception of considerable interest. In this preliminary communication some experiments are described which were undertaken to determine whether any E. M. F. is developed when organic compounds are broken down through the fermentative activity of yeast and other organisms. Cultures of Saccharomyces cerevisiae and certain species of bacteria were grown in nutrient media, and the chemical action of their vital processes was utilised to develop electrical energy in a manner parallel to the production of E. M. F. by means of the ordinary galvanic cell.

On a New Method of Estimating the Aperture of Stomata

Abstract: It is usually assumed that transpiration is regulated by two principal factors: (1) the relative humidity of the air, and (2) the degree of aperture of the stomata. Neither of these assumptions has been experimentally proved, though both of them are necessarily true, but it must be remembered that the factors referred to are not necessarily the only ones that govern the phenomena. The experiments hitherto made on (1) the effect of relative humidity are vitiated by want of precise knowledge as to the stomatal aperture during the course of the enquiry.

The Action of Animal Extracts on Milk Secretion

Abstract: Since the secretion of milk is known to proceed with the same regularity whether the nerves to the mammary glands are cut or intact, it seems probable that is is provoked by other than nervous stimuli. It cannot, indeed, be contested that the secretion is influenced through the nervous system, but this may be indirect, if the formation and outpouring of the secretion can be shown to be produced by chemical agents (hormones) circulating in the blood, such as have been found to excite secretion in the pancreas, which is stimulated to active secretion by a material obtained from the mucous membrane of the duodenum, and in the kidney, which is stimulated by a material yielded by the posterior or infundibular portion of the pituitary body. We have investigated the action of a large number of animal extracts upon the flow of milk from the mammary glands of lactating animals, chiefly cats, but including some dogs. The extracts, which were made with Ringer’s solution and were in most cases previously boiled, were injected slowly and in small amount (not more than 5 c. c at a time) into a superficial vein, and the flow of milk, if any, was recorded by one of two methods, or by both methods simultaneously. The simpler method consists in recording the rate of exudation of milk from a small and superficial cut into one of the mammary glands (exudation method). The other method consists in recording the flow of milk led from a canula tied into a cut nipple (nipple method); in either case the milk is allowed to drop upon an electric recorded, and the drops are marked by an electromagnetic signal upon the paper of a kymograph. On this paper are also recorded at the same time in some of our experiments the blood-pressure, the volume of the kidney, and the rate of excretion of urine. The animals were anaesthetised either with chloroform alone or with chloroform followed by chloral, the latter being administered either intravenously or subcutaneously; after the complete effect of the chloral is established, the chloroform administration is stopped.

A Case of Gametic Coupling in Pisum

Abstract: For some years past a variety of culinary peas has been grown at Verrieres-le-Buisson, remarkable for the fact that it has no tendrils, each of the normal tendrils being represented by a leaflet. The figure shows the appearance of the leaves of this variety, with leaves of normal plants for comparison. These “Acacia” peas, as they are called, breed perfectly true. Their origin is unknown. The variety has wrinkled seeds.

Experimental Researches on Vegetable Assimilation and Respiration. IX.-On Assimilation in Submerged Water-Plants, and Its Relation to the Concentration of Carbon Dioxide and other Factors

Abstract: The fourth paper of this series contained an account of quantitative investigations on the magnitude of assimilation in the leaves of land-plants under different conditions of illumination and temperature. The general conclusion reached was that the actual magnitude of assimilation in a leaf at any moment is determined by one or other of the main controlling conditions, light, temperature, or CO2-supply, acting as a limiting factor.

On the fate of red blood corpuscles when injected into the circulation of an animal of the same species; with a new method for the determination of the total volume of the blood

Abstract: In a paper published last year the authors described a method by which it is possible to recognise the red blood corpuscles of any individual ox and to differentiate them from those of any other member of the same species. The method depends upon the fact that if a highly polyvalent isohaemolytic serum is treated repeatedly with the red blood corpuscles of any individual of the species for which the serum has been made, it entirely loses its haemolytic action for the corpuscles of all other individuals of the same species. Such a serum therefore constitutes, so to speak, a specific reagent for the corpuscles of the individual for which it has been prepared, and by its means one is enabled to follow up and to identify these corpuscles even in the presence of corpuscles of other individuals.

Reversal of the Reflex Effect of an Afferent Nerve by Altering the Character of the Electrical Stimulus Applied

Abstract: Stimulation of an afferent limb-nerve in the decerebrate or decapitate mammal (cat, dog) gives as its reflex result flexion of that limb; during this flexion the pure extensor muscles of the limb relax under central inhibition. In the hind limb this reflex effect is observable in the isolated vasto-crureus, the main extensor muscle of the knee; that muscle if engaged in contraction relaxes when the afferent nerve is stimulated. Its elongation is the sign of the central inhibition which takes place. If the reflex stimulation be strong the muscle relaxes quickly and greatly; if the stimulation be weak the relaxation is slower and less ample. These results are easily demonstrable by using as a stimulus either faradism or mechanical stimulation such as ligation of the central stump of the afferent nerve. Usual and uniform as this result is, we find it possible in the decerebrate preparation under certain conditions to obtain reflex contraction of vastocrureus as well as reflex inhibition, and to elicit the contraction through the same afferent nerves as under other conditions so regularly elicit inhibition. The condition influencing the nature of the reflex result in this respect are (1) the strength and (2) the form of the electrical stimulus applied to the afferent nerve, and (3) the reflex state obtaining in the preparation at the time.

Cancerous Ancestry and the Incidence of Cancer in Mice

Abstract: The purpose of these experiments has been the collection of data sufficiently abundant and accurate to determine whether an enhanced liability to cancer is transmitted in the case of mice from parents to offspring. In a preliminary note in 1909 a short account was given of the manner in which these experiments have been conducted. The animals have all been housed and fed in a uniform manner in one room. They have been kept in large cages,which have been cleaned regularly, and the environment has been as uniform as it has been possible to make it. During the past five years nearly 1600 animals have been bred, the two sexes contributing approximately equal numbers. Of them, 562 females which have lived for six months or more form the material of the present paper. The incidence of the disease is so dependent on the age and sex of the animals that, in order to get comparable groups, only mice of the same sex and of approximately the same age may be reckoned together. They have been arranged in age-periods of three months’ duration, this being the shortest interval which gives reasonably large figures in each group.

Further researches on the development of trypanosoma gambiense in glossina palpalis

Abstract: The object of these experiments was to try to discover if there is any definite cycle of development of the trypanosome of Sleeping Sickness in the tsetse fly, Glossina palpalis , and if the late or renewed infectivity of the fly coincides with any phase in this development. The mode of experimentation was to feed a cageful of laboratory-bred tsetse flies on an animal whose blood contained numerous trypanosomes, and at the end of various times to kill the flies and examine their intestinal contents. This was done for periods of one day, two days, three days, and so on, up to 56 days. The microscopical examination of preparations made from the intestinal contents on the various days gave information as to the number and appearance of the trypanosomes.

On the Factors Concerned in Agglutination

Abstract: Of the various reactions which can be observed to take place between antigen and antibody, agglutination has usually been looked upon as relatively simple. It has been assumed that the clumping of bacteria or red cells is produced by the action of substances known as agglutinins. According to the well-known views of Ehrlich, an agglutinin is possessed of two groups, a cytophile or haptophore group which fixes on to the cell, and a group which has the property of producing agglutination. According to another view the cell or bacterium combines with its specific antibody, and the combination of cell and antibody is then clumped by the action of electrolytes. A broad distinction has, however, always been drawn between such phenomena as precipitation and agglutination, which appear to represent a comparatively simple reaction between antigen and antibody, and those more complex effects such as haemolysis and bacteriolysis in which another the specific action of the antibody. Observations published by Muir and Browning (1906) suggested, however that in some instances, at any rate, the mechanism of agglutination may be more complex.

A contribution to our knowledge of the protozoa of the soil

Abstract: In the ‘Journal of Agricultural Science,’ Vol. III, Part 2, 1909, Drs. Russell and Hutchinson of this laboratory published an account of their investigations on the effect of partial sterilisation of soil on the production of plant food. In this paper it is shown that, when soils are heated or treated with certain volatile antiseptics, and brought again under conditions favourable to plant growth, they show a great increase in fertility. It is further shown that, although the bacteria are at first reduced very considerably in numbers, yet under conditions of temperature, moisture, and aeration favouring growth, they subsequently increase enormously in numbers. Pari passu with this increase in the number of bacteria, there is an increase in the production of ammonia in the soil, and it is to this that the soil owes its greater power of production. In explanation of these results, the theory is advanced that the treatment by heating or with antiseptics has removed some factor which in the untreated soil normally limits the growth of bacteria, and thus the rate of ammonia production. This limiting factor is looked upon as being biological in character, but not of a bacterial nature.

The physiological influence of ozone

Abstract: Ozone has been extolled as the active health-giving agent in mountain and sea air, its virtues have been vaunted as a therapeutic agent, until these have, by mere reiteration, become part and parcel of common belief; and yet exact physiological evidence in favour of its good effects has been hitherto almost entirely wanting. Ozone has been found occasionally in traces in the atmosphere, it has been proved to have active oxidising properties, and on these facts the superstructure of its therapy has been reared. Popular attention has been fixed on the mysterious and the unknown, and has neglected the prepotent power of cold wind and sunlight to influence the nervous health and metabolism of man. The only thoroughly well-ascertained knowledge concerning the physiological effect of ozone, so far attained, is that it causes irritation and œdema of the lungs, and death if inhaled in relatively strong concentration for any time, e. g. , 0·05 per cent., death in two hours (Schwarzenbach); 1 per cent. In one hour (Barlow).

Motor localisation in the brain of the gibbon, correlated with a histological examination

Abstract: Motor localisation in the Gibbon has not been hitherto determined experimentally, probably owing to the difficulty of obtaining a suitable animal. It appeared to be desirable, therefore, to see whether the habits and mode of life of this animal could be correlated with an increased development of the motor cortex. One of us (F. W. M.) had some years ago, by a comparative study of the convolutional pattern of the brains of Lemurs and Apes, made the following deduction: “The remarkable use this animal makes of its arms and hands can be correlated with a remarkable expansion of the cortex in the precentral region, as shown by the development of a broad gyrus extending from the middle of the precentral region to form the second frontal convolution. Now if we turn to the Ape’s brain (Maeacus), and see what the effect of this development would be, we observe that it would push forwards and downwards that portion of the cortex which on stimulation gives rise to movement of the head and eyes, particularly that which gives rise to eye movements, etc.” Figures were shown to indicate that the sulcus arcuatus would be pushed down to join the sulcus rectus. The following experiments by stimulation, correlated with a complete histological examination of the cortex in front of the central sulcus, have confirmed this deduction. The animal used for the experiments was a male and black in colour; it was remarkably agile; when standing or running on the ground it maintained almost an erect posture, using its long arms to balance itself very much as a man would walk on a tight rope with a- balancing-pole. It was kept for some days before the experiment in the animal room of the Physiological Laboratory, Liverpool, and it was frequently heard to utter vocal sounds of very varying pitch and quality. Thus it could imitate the shrill high-pitched whistles of the guinea-pig and the relatively low-pitched bark of the dog. A short account of the larynx of this animal will be made the subject of a future publication.

On the Inter-Relations of Genetic Factors

Abstract: The nature and bearing of the observations to be recorded in this paper will best be explained by tracing the steps by which they have been reached. Early in the investigation of heredity in the sweet pea it was observed that when plants were heterozygous for two separate pairs of allelomorphs the distribution of the factors concerned was in certain cases disturbed in definite ways, such that particular combinations occurred in the gametes with greater frequency than others.

The life-history of Trypanosoma gambiense and Trypanosoma rhodesiense as seen in rats and guinea-pigs

Abstract: The researches recorded in this paper were undertaken at the suggestion of Major Ross, who wished me to investigate the parasitological aspect of the numerical cyclical development discovered by him and Dr. D. Thomson (1910) in the trypanosome occurring in a patient suffering from Sleeping Sickness contracted in Rhodesia, particularly as regards the possible connection of the latent bodies of Salvin-Moore and Breinl (1907) with that cycle. The investigations have been conducted in the Liverpool School of Tropical Medicine, under a grant from the Tropical Diseases Research Fund. A complete and generally accepted life cycle of Trypanosoma gambiense has yet to be written. The following paper is offered as a contribution to the solution of this difficult problem, and deals with that portion of the life history of the parasite which takes place in a Vertebrate host.

The Action of Bacillus actis aerogenes on Glucose and Mannitol. Part II.-The Investigation of the 2:3 Butanediol and the Acetylmethylcarbinol Formed; the Effect of Free Oxygen on their Production; the Action of B. Lactis aerogenes on Fructose

Abstract: A preliminary communication on some of this work has been published. The present paper deals with the experimental part of the investigation in question, and some new results are recorded. On examining the action of B. lactis aerogenes on glucose, it was found that the carbon content of the present containing the amount of carbon needed to explain this discrepancy. As, in the preliminary communication, justification was shown for calling this liquid “crude butylene glycol,” the use of this convenient name will be continued here. The object of this investigation was to determine as far as possible the nature of the contituents of this material, and the proportions in which they are found therein. The Conditions of Cultivation of the Organism. In all the earlier experiments the organism ( B. lactis aerogens ) was grown anaerobically in a medium containing 1 per cent. of Witte peptone, per cent. of pure glucose, and an excess of chalk. Later, other sugar were used, and sometimes, when using glucose, the percentage of sugar employed was raised to 5, in order to obtain larger yields of one particular product per litre of medium treated. The flasks employed were of 1 litre capacity, and each was provided with a mercury trap which permitted the egress of the gases evolved. The fermentation was carried on under strictly anaerobic conditions, and the method of preparing the flasks was that employed nu Harden. While in the incubator the medium. The gas evolution was found to be vigorous during the first four days, but after two to four weeks ceased completely, and the quantity of unchanged sugar in the flask was very small indeed.

On gametic coupling and repulsion in Primula sinensis

Abstract: In Primula sinensis the short style is dominant to the long style, and the magenta colour of the flower is dominant to the red colour. Some years ago a series of experiments was made, in which a red short-styled race was mated with various long-styled plants carrying the factor for magenta colour. In F2 from these crosses, only three kinds of offspring were obtained, namely: (1) magenta, short-styled; (2) magenta, long-styled; (3) red, short-styled. No red long-styled. No red long-styled offspring were produced. This results shows that, in the gametogenesis of the F1, complete repulsion took place between the factors for the two dominant characters, magenta and short style.

The Permeability of the Yeast-Cell

Abstract: The question of the permeability of plant membranes and of the protoplasm lining plant cells has received just attention from time to time, the method usually employed being based upon plasmolysis, a phenomenon first described by Nageli in 1855 (1), and subsequently investigated by Pfeffer (2), De Vries (3), and Overton (4). The results of their experiments tend to show that purely physical diffusion laws cannot always interpret osmotic phenomena as exhibited by living plant cells, but that in some cases there is evidence of specific permeability. Nathanson (6) finds that the permeability of protoplasm for any substance is not constant, but varies according to the concentration within and without the cells, and he holds that these variations cannot be accounted for in a purely physical manner.

Gametogenesis of the Gall-Fly, Neuroterus lenticularis.-Part II

Abstract: In the first part of this paper I described the life-history, spermatogenesis, maturation of the fertilised egg, fertilisation and segmentation divisions of the summer generation of the gall-fly Neuroterus lenticularis ( Spathegaster baccarum ), and gave some observations on the maturation of the eggs of the spring generation, and on the somatic mitoses in males and females. These latter observations were admittedly incomplete owing to lack of material, and this second part of the paper attempts to complete the account of what was left uncertain in the first communication. Before proceeding to describe my fresh observations it may be well shortly to summarise the results arrived at in the fist part. The spring generation of N. lenticularis consists of females which lay parthenogenetic eggs; those laid by some females develop into sexual females, both of which hatch in June. The eggs of the summer females undergo a double maturation division, leaving 10 chromosomes in the nucleus of the mature egg. The spermatogonia of the males in the same generation have 10 chromosomes; the first spermatocyte division is suppressed; in the second spermatocyte division the chromosomes divide, 10 entering each spermatid. A small staining extra-nuclear body found in the spermatocytes does not divide, and is included in only half of the spermatids. In fertilisation, the egg and sperm nuclei each contain 10 chromosomes, and the segmentation divisions of the fertilised egg show 20. For a complete study of the maturation and segmentation of the parthenogenetic spring eggs my material was insufficient, but it suggested that the eggs laid by some females underwent maturation and showed 10 chromosomes in the segmentation divisions, and that others had no polar divisions and showed 20. Since somatic and oogonial mitoses of the summer female have 20 chromosomes, but the spermatogonial mitoses and those of the developing nervous system in the male only 10, it was suggested that the eggs which undergo maturation produce males, the others females. An attempt was made, in conclusion, to connect these phenomena with what is know of sex-determination in other animals.

Auto-Agglutination of Red Blood Cells in Trypanosomiasis

Abstract: Introduction .—It is now a well recognised fact that the erythrocytes in fresh preparations of the blood of Sleeping Sickness cases and animals infected with trypanosomiasis frequently exhibit a more or less marked degree of agglutination. Attention was first drawn to this phenomenon n 1898 by Kanthack, Duraham and Blandford, who found that the red blood cells of animals infected with nagana, instead of forming rouleaux, tended to clump together into masses and to lose their outlines. More recently Christy (1904), Dutton and Todd (1905), Martin, Labœuf and Roubaud (1906-8), and others have described a similar condition in fresh preparations of the blood of patients suffering from Sleeping Sickness.

On Ceratopora, the Type of a New Family of Alcyonaria

Abstract: In the introduction to the British Museum Catalogue of the Jurassic Bryozoa (1896), Gregory remarks that, “to the palaeontologist, who cannot check his conclusions by the evidence of vascular anatomy or embryology, these tube-dwelling animal are a vexation and a puzzle.” This passage has reference to the difficulties that the palaeontologist meets in determining the proper systematic position of many fossils that are known to us only by the tubular skeleton that they have left deposited in the rocks. Simple or colonial tubular skeletons, or more correctly shells, may be formed for the protection of recent sedentary animals belonging to the Protozoa, Cœlenterata, Annelida, Polyzoa, and Mollusca, and in many cases the only trustworthy guide to their systematic position is to be found in the study of the soft structures that formed the shell, the shell itself affording no distinctive characters. In some cases the presence of septa, and in others of tabulae, may indicate affinities; even these characters may be misleading and give rise to erroneous conclusions. The presence of septa-now called pseudosepta-in Helipora led to the erroneous conclusion that Heliopora was a Zoantharian coral, and the presence of tabulae in Millepora led to the classification of the Milleporidae with other tabulate corals. It was not until Moseley examined the soft arts of Heliopora, and until Agassiz examined the soft parts of Millepora, that these corals were assigned to their proper in the animal kingdom.

The Morphology of Trypanosoma gambiense (Dutton)

Abstract: This species, like Trypanosoma brucei , is markedly dimorphic. In size and general appearance also these two species so closely resemble one another that one might easily believe them to be varieties of the same species. There are, however, some slight differences in morphology, which will be described below; but whether these differences will bear the test of more extended observations remains to be seen. It may be noted that the trypanosomes described come from Uganda, and are not mixed up with strains from the Congo or Rhodesia. A. Living, Unstained. Trypanosoma gambiense also resembles Trypanosoma brucei in having little or no translatory power when viewed alive in the field of the microscope.

The Alcoholic Ferment of Yeast-Juice. Part VI.-The Influence of Arsenates and Arsenites on the Fermentation of the Sugars by Yeast-Juice

Abstract: The rate of fermentation of a simple sugar by yeast-juice undergoes a temporary acceleration when a soluble phosphate is added. The close chemical analogy which exists between phosphates and arsenates suggested the idea that this similarity might extend to the effect of arsenates on fermentation, and accordingly experiments were made to test the point. It was thus found that arsenates have a great effect on fermentation, but subsequent work has show that it is of a totally different nature from that exerted by phosphates. I. Influence of Arsenate on the Rate of Fermentation . When a solution of sodium arsenate is added to a mixture of glucose, mannose or fructose with yeast-juice, which has attained a steady rate of fermentation, an immediate large increase in the rate of evolution of carbon dioxide is produced. The rate, as a rule, rises for a short period, attains a maximum, and then very gradually diminishes. A typical example is the following.

The Mechanism of Carbon Assimilation: Part III

Abstract: Some experiments and conclusions recorded in two papers published in 1906 have been subjected to criticism by several investigators, and the present paper has been written with the object of presenting some new facts bearing on the problem of carbon assimilation, which incidentally support some of those conclusions. We also take this opportunity to restate the theory originally advanced, with such modifications as may be necessary, and to reply to a few of the more important objections to it which have been raised. The observations recorded below are concerned only with the initial stages of the photosynthetic process, that is to say, with the formation of the primary photolytic products from carbon dioxide, and with the evolution of oxygen. In the papers referred to some evidence was given in support of the belief that aqueous carbon dioxide is decomposed by light under the conditions obtaining in a green leaf, the immediate products of this decomposition being hydrogen peroxide and formaldehyde; and it is easy to see that the production of these two substances would satisfactorily account both for the oxygen and the carbohydrate, which are the first visible results of the natural process. As the evidence put forward was to some extent indirect, wholly so in the case of hydrogen peroxide, it was thought advisable to supplement it by further experiments.

On Reflex Inhibition of the Knee Flexor

Abstract: Study of reflex inhibition has been prosecuted more with extensor centres than with flexor. In the case of these latter, the experimental examination of the inhibition is of necessity somewhat differently circumstanced than in the case of the extensors. For both there is requisite a suitable background of reflex excitement against which inhibition may be evident. With the extensors this reflex background of excitement can be provided by postural tonus, and such tonus is readily obtained by use of the decerebrate preparation. With the flexors there is at present no procedure available for providing such tonic preparations. Recourse has to be taken to theproduction of reflex excitation of the centres by artificial stimuli applied to some appropriate afferent channel.

Inbreeding in a Stable Simple Mendelian Population with Special Reference to Cousin Marriage

Abstract: The Mendelian theory of the segregation of unit characters, though it is far, as yet, from being completely demonstrated, offers a simple explanation of some striking features of inheritance. In particular, Mr. E. C. Snow has recently shown that the gametic correlations for collaterals deducible from the Mendelian hypothesis are in close agreement with the actually observed somatic correlations for man and certain other animals; or, in other words, that a Mendelian theory of segregation without dominance gives values for collateral resemblance not greatly differing from those found from observation. It seems, therefore, possible that the same theory will throw some light on the problem of inbreeding, or, at any rate, will indicate to what points, on which precise data are at present lacking, statistical enquiry should be directed. Without these data the Mendelian theory cannot be corroborated or negatived by the methods of the present paper. So far as they go, however, the statistics at present obtainable with regard to consanguinity in the parentage of albinos and deaf mutes are in approximate agreement with the calculated results, although the accuracy of the figures is too uncertain for the application of anything more than a rough criterion.

The Action of X-Rays on the Developing Chick

Abstract: This research was undertaken at the suggestion of Prof. Grunbaum, in order to discover whether any changes were produced in the chick embryo under the action of X-rays. Embryos of various ages were examined, both directly after exposure to doses of various amounts, and also at later periods. In none were any observations obtained of changes either in the embryo as a whole or in any particular organ, with the exception of one which affected all the tissues so exposed. It was found that X-rays had a general effect on the rate of division of the cells of the embryo, causing a diminution in the number of mitoses. This diminution was very evident in embryos exposed to long doses; for instance, chicks incubated for three days and then given a two hours’ exposure, showed so marked a diminution that a considerable search was required to find any mitotic figures, while in an embryo of three days, exposed for four hours, no mitotic figures could be found.

The pharmacological action of South African boxwood (Gonioma kamassi)

Abstract: The boxwood products with which the following experiments were performed were prepared from the wood of Gonioma kamassi exported from Knysna and belonging to the N.O. Apocynaceae. The wood was carefully identified and sent in sealed parcel to Mr. E. F. Harrison, who extracted an alkaloid. The certain identity of the wood is of some importance, as the preparations which were used in my experiments cannot be called into question and as there has been some confusion in the past between Gonioma kamassi (South African box), Buxus macowani (East London boxwood) and Sarcocephalus diderrichii (West African boxwood)

A Case of Sleeping Sickness Studied by Precise Enumerative Methods: Further Observations

Abstract: In a previous paper by us, published in the ‘Proceedings’ of July 21, 1910, B 557, we recorded our observations on this case during two and a-half months, and described particularly the regular periodical rises in the numbers of trypanosomes disclosed in the patient’s peripheral blood by methodical daily countings extending over that period. Our technique has been detailed in another paper by us on “Enumerative Studies on Malarial Fever,” recently submitted to the Society. We now record our further observations on the case during two more months—until the patient’s death. A chart and a table giving daily details of the observations are attached; and accompanying papers by Drs. J. G. Thomson and H. B. Fantham record studies on animals and on the parasites themselves. We must refer also to a recent communication to the Society by Drs. J. W. W. Stephens and Fantham suggesting that the species found in this case may not be identical with T. ganibiense . The patient, a strong young Englishman, age 26, weight 154 lbs., was infected in N. E. Rhodesia near the River Luangwa in September, 1909. The trypanosomes were found in his blood in Africa on November 17.