Abstract
LONDON. Royal Society June 15.—Sir Archibald Geikie, K.C.B., president, in the chair.—Prof. T. G. Brodie: Croonian lecture: A new conception of the glomerular activity. All the more recent work upon the kidney has proved conclusively that Ludwig's explanation of the glomerular function, viz. that the glomerulus is a filtering mechanism, is incorrect. The structural details of this highly characteristic portion of the renal apparatus strongly suggest that in some way or other the blood pressure is made use of in the work of the glomerulus. Having excluded filtration in this connection, there is yet another way in which it could be directly utilised, viz. in setting up a pressure-head by means of which the watery part of the urine could be driven through the very long and narrow tubule. In reference to this side of its activity, it is suggested that the glomerulus be termed a “propulsor.” An approximate calculation of the pressure-head necessary to drive the fluid along the tubule during the height of activity proves that one about equal to that present within the glomerular capillaries is required. Evidence of the action of a high intra-tubular pressure is at once obtainable from the microscopic examination of a kidney after activity. The capsules of Bowman are greatly distended and approximately spherical in shape, the glomeruli are moderately enlarged and no longer fill the capsular spaces. The tubules are straightened out, stretched, and possess a conspicuous lumen. All these changes are exaggerated by any procedure which favours the action of this intra-tubular pressure, such as a high arterial blood pressure, obstruction to the outflow of urine from the ureter, or the stripping of the capsule from the kidney. Further, the kidney during activity is tense and hard, and distends its capsule to the utmost. This conception of the glomerular function affords a complete explanation of the existence of a firm and inextensible capsule surrounding the kidney, as also of such phenomena as the maximum ureter pressure; the dependence of the rate of discharge of urine from the kidney upon the general blood pressure, and the degree of dilatation of the renal arterioles, &c. Applying this theory to the study of the action of diuretics in animals in which the blood pressure has been lowered so far that propulsion can no longer occur, we obtain evidence as to the parts of the renal tubules acted upon by these different substances.—A. R. Cushny: The action of Senecio alkaloids and the causation of hepatic cirrhosis in cattle. Various species of Senecio (ragwort) have been shown to induce fatal poisoning in cattle and horses in South Africa, Canada, and New Zealand. The alkaloids of one of these species were isolated by Watt, and their pharmacological examination shows that they induce the same symptoms as the entire plant. The Senecio species in this country proved non-toxic, except the common groundsel (S. ovulgaris), and extracts from the ragwort grown in Canada, where the plant is poisonous, proved devoid of action also. This may, however, be due to the season at which the plant was gathered.—G. Buchanan: Note on developmental forms of T. brucei (pecaudi) in the internal organs, axillary glands, and bone-marrow of the gerbil.—Captain W. B. Fry: A preliminary note on the extrusion of granules by trypanosomes.
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Societies and Academies . Nature 86, 606–610 (1911). https://doi.org/10.1038/086606b0
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DOI: https://doi.org/10.1038/086606b0