Abstract
LONDON. Royal Society May 4.—Sir Archibald Geikie, K.C.B. president, in the chair.—Dr. F. W. Mott, Edgar Schuster, and Prof. C. S. Sherrington: Motor localisation in the brain of the Gibbon, correlated with a histological examination. A comparative study of the convolutional pattern of the brains of lemurs and apes led to the expectation that the remarkable use the Gibbon makes of its arms and hands would be found by experiment and histological investigation to be correlated with the remarkable expansion of the cortex cerebri 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. This development, it was inferred, would push downwards and forwards that portion of the cortex which on stimulation gives rise to eye movements in Macacus. Stimulation experiments by unipolar excitation are given in detail showing the correctness of this deduction; moreover, for the first time the excitable motor cortex is precisely mapped out in this animal. The experimental observations have been correlated with a histological survey of the cortex cerebri in front of the central fissure. Figures are given to show the distribution of two quite distinct types of cortex in the lateral surface of the Gibbon's brain in front of the central fissure corresponding to Campbell's precentral and intermediate precentral types, or to Brodmann's types 4 and 6. The great forward extension of the intermediate precentral area (especially that which may be described as the middle frontal convolutions) forms a most characteristic feature of the Gibbon's brain, and distinguishes it in a very striking way from the Orang and Chimpanzee on the one hand, and Cercopithecus and the Baboon on the other.—J. S. Huxley: Some phenomena of regeneration in Sycon, with a note on the structure of its collar-cells. Production of normal individuals from isolated cells (as in Wilson's experiments on Monaxonida).—Cells were obtained singly by straining sponges through gauze. They first unite into lumps, all the kinds being confusedly mixed (reunion). Next the dermal cells migrated to the surface to form a flat epithelium round a mass of quiescent collar-cells (reorganisation). Then came redevelopment: spicules arise, monaxons before triradiates; gastral cavity and osculum appear. The spicules form later than in the larva (where, however, they are certainly precocious), and the regenerates failed to fix permanently. Otherwise redevelopment resembled normal post-larval development. None became heteroccelous, though one lived and grew as a functioning sponge for several weeks. The fate of the cells here is not a function of their position, for they have to migrate into position before development can proceed. Behaviour of pure collar-cells.—If large bits of gastral epithelium are taken, they bend back and round up into perfect hollow spheres with collars directed outwards. Similar spheres were formed, but in a different way (with preliminary solid stage), if numerous single cells were taken. Though some lived more than a month, no other tissue was regenerated by them. These spheres have no bearing on phylogeny. Their structure is probably due only to oxygen requirements and to surface tension. Their failure to regenerate other tissue proves nothing against choanoflagellate ancestry; the ancestral cells may have given up their regenerative powers to others, more suited, as has happened elsewhere (e.g. Ascidians). Collar-structure.—Longitudinal rods do exist in the collar, as described by Bidder.—Dr. J. A. Murray: Imperial Cancer Research Fund. Cancerous ancestry and the incidence of cancer in mice. The present paper is in continuation of a previous communication (Roy. Soc. Proc., B, vol. lxxxi., 1909, p. 310). The analysis of the ancestry of 1600 mice bred in the laboratory has permitted their classification in two groups differing considerably in the incidence of cancer. Out of a total of 562 female mice which lived for six months or more, cancer had occurred in the mother, one or other grandmother, or all three in 340, and in them 62 developed cancer of the mamma (18-2 per cent.). In the remaining 222 mice in which cancer was absent from the maternal and grandmaternal ancestors, only 19 developed cancer of the mamma (8.6 per cent.). The group with recent cancerous ancestry is found on analysis Ho be more severely attacked at all age-periods than the non-cancerous group (cancerous ancestors remote). Detailed analysis of the ancestors enhances the importance of the differences. The differences exceed their standard errors sufficiently to render them significant. The predisposition is apparently not constitutional, but local, and is regarded as only one of the factors in the development of cancer.—Dr. R. Tanner Hewlett: Immunisation by means of bacterial endotoxins. The action of bacterial endotoxins in immunising against the corresponding living organisms has been investigated. Guinea-pigs were the animals employed. Typhoid Endotoxin.—Series of guinea-pigs were given single injections of the endotoxin, ranging from 0–01 mgrm. to 1-0 mgrm. Five to eleven weeks later the animals were injected with living typhoid culture; considerable protection was obtained, particularly with doses of 0–1 and 1-0 mgrm. The protection afforded by the endotoxin was better, and lasted longer than that conferred by a baciliary typhoid vaccine. Cholera Endotoxin.—Six guinea-pigs each received 0–25 mgrm. of the endotoxin, and all survived an injection of living cholera culture given eleven weeks later. Diphtheria and Plague Endotoxins similarly confer some protection against the living organisms. No immunising substance was obtained from the Trvpanosoma brucei. The results suggest that bacterial endotoxins may be of considerable value as protective vaccines. The endotoxin solutions maintain their activity for some weeks at least, probably for a much longer period. A few inoculations of typhoid and diphtheria endotoxins have been performed in the human subject. The inoculations cause some local reaction at the site of inoculation, but little general reaction. (The endo-toxin solutions were prepared by the method described in Roy. Soc. Proc., B, vol. Ixxxi., 1909, p. 325.)—J. E. Barnard and Dr. R. T. Hewlett: A method of disintegrating bacterial and other organic cells. Bacterial toxins are of two kinds, extra-cellular and intra-cellular. The former are excreted into the medium, e.g. beef broth, on which the organism is cultivated, so that by a process of filtration the organisms can be removed, and the toxin is obtained in the filtrate; but the majority of pathogenic micro-organisms do not excrete their toxins, at least to any extent, and the toxins are retained within and form integral parts of the cells of the organisms. One method of obtaining these toxins is mechanically to disintegrate the bacterial cell, so that the cell contents are expressed, and the apparatus here described accomplishes this. It consists essentially of a containing vessel, in which, by a suitable rotation of steel balls, the organisms are crushed. The principal conditions to be fulfilled in such an appliance are:-Approximately every cell should be brought under the grinding action. Little or no rise of temperature should take place. The disintegration must be carried out in a vessel which is sealed, so that, when dealing with pathogenic organisms, none can escape at any stage of the process. These conditions are, in the main, complied with in the apparatus described. Experiments indicate that by this method the cell-juices are obtained unaltered, and suitable for investigations on the chemical composition and properties of the bacterial proteins and other cell constituents. Also that, after the grinding process has been carried on for a sufficient time, practically no cells remain which can be properly stained by any recognised bacteriological method, and which therefore can be regarded as whole cells containing a normal quantity of cell-juice.
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Societies and Academies . Nature 86, 370–372 (1911). https://doi.org/10.1038/086370a0
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DOI: https://doi.org/10.1038/086370a0