Societies and Academies

Abstract

LONDON.Royal Society, March 28.—Sir Archibald Geikie, K.C.B., president, in the chair.—Dr. G. J. Burch: A confusion test for colour blindness. A sheet of perforated zinc is fixed in the focal plane of a convex lens of about eight diopters, through which the observer looks. On a card six in. or so farther off is painted a design in confusion colours, e.g. red and blue letters on a dark-green ground. The red-blind can distinguish the blue letters but not the red, though these are far more conspicuous to the normal. The letters being out of focus, brush marks are invisible, and new designs can be easily drawn. Other colours are: Geranium red with French grey; emerald green with yellow ochre; lilac with blue-this last being a test also for the green-blind.—Clifford Dobell: The systematic position of the Spirochæts. The paper is a brief summary of certain results obtained from a detailed study of the morphology of a large number of Spirochasts and related organisms. It is maintained that the Spirochsets cannot be regarded as Protozoa, but that they must be classified among the Schizophæts, and that in the latter group they must be placed among the Bacteria and not among the Cyano-phyceas.—E. C. Snow: The influence of selection and assortative mating on the ancestral and fraternal correlations of a Mendelian population. Using the simple hypothesis of Mendel, the author investigates by analytical methods the numerical effect on the ancestral and fraternal correlations of dealing with samples (a) which are not true random samples of the general population and which mate with no sexual selection; (b) which are perfectly random samples of the general population but mate with certain intensity of assortative mating; (c) which are selected samples showing assortative mating. So far as numerical results are concerned, the investigation supports the view that the Mendelian hypothesis can be employed to give confirmation to results which have at first sight appeared paradoxical (e.g. the closeness of the resemblance between first cousins) and to give a rough indication of the probable results in cases for which actual statistical data are inadequate (e.g. the inquiry into the effects on the offspring of inbreeding of various degrees).—T. Lewis and M. D. D. Gilder: The human electrocardiogram; a preliminary investigation of young male adults, to form a basis of pathological study.—C. Revis: The production of variation in the physiological activity of Bacillus coli by the use of malachite-green. Bacillus coli can be trained to grow in nutrient broth containing malachite-green. By gradually increasing the percentage of the malachite-green the organisms will develop readily in presence of O'IO per cent. In most cases the organism at the same time undergoes a profound change in its physiological activitv towards sugars and polyhydric alcohols, acid only being produced in certain of these, from which the organism originally produced both acid and gas, the power of gas formation being permanently lost. In one instance this change in physiological activity was accompanied by equally profound omorphological and cultural changes, the resultant organism being quite different from that from which it had been produced. The chansre brought about by mala-chite-green indicates a connection between the typhoid and coli groups and the possibility of development of organisms of the one into those of the other.-Muriel Robertson: Notes on some flagellate infections found in certain Hemiptera in Uganda.-Muriel Robertson: Notes on certain aspects of the development of T. gambiense in Glossina palpalis.—Dr. H. L. Duke: Antelopes and their relation to trypanosomiasis.—F. P. Knowlton and Prof. E. H. Starling: The nature of pancreatic diabetes (preliminary communication).