166 R~.VIEWS.

The Secretion of the Urine. By ARTHUR R. CUSHNY, M .A., M.D.,

LL. D., F.R.S., late Professor of Materia Medica and Pharmacology in the University of Edinburgh. Second edition. London: Longmans, Green & Co., Ltd .• 1926. Price 16s. net.

THE death of the distinguished author of this monograph, which occurred in l<'ebruary last, only a few days after he had written the short preface to the pre3ent edition, is a great loss to medical science. The first edition, Pllblished in 191], gave a pOlVerful stimulus to research into the physiology of the kidneys. and, in fact, It has been the starting-point of all the important work in that connection which has since been carried out. In that edition Cushny, after critical consideration, rejected, as unproved and inadequate to explain the facts, the theories associated with the names of Ludwig and Heidenhain, which lor nearly half a century had divided the opinion of physiologists, and propounded what he termed the "modern view" of the secretion of the urine. This theory accepts the general scheme of filtration and reabsorption of Ludwig, but, recognising the inadequacy of the known physical forces. it adopts to some extent the vital activity or secretory theory postulated by Heiden hain in order to explain the reabsorption which occurs in the renal tubules. It sees in the secretion of the urine two distinct processes, viz., ([) filtration, which occurs in the glomeruli; and (2) reabsorp­tion, which occurs in the tubules. According to Cushny, the glomerular filtrate i, practically deprotcinised plasma, and its formation is due to "a blind physical force. " The absorption which occurs in the tubules is equally independent of any disc rimination, for the fluid absorbed is always the same, whatever the needs of the organism at the moment. In its passage through the tubules, however, the fluid is altered by the absorption of certain of its constituents, and as this entails the expenditure of energy by the epithelial cells it must be regarded as an active process, not the passive diffusion which was believed to have been sufficient by Ludwig.

In the present edition the" modern theory" is re examined and restated in the light of the work that h l S recently been c:Jfried out, and it was the opinion of the aurh')r that the new (acts have greatly stren gthened the point of view which was advocated in the first issue. It is admitted, however, that filtration and reabsorption may prove insufficient to account for the formation of the urine, and that specific secretion may have to be called in to supple­ment them. So far this has not seemed necessary, and efforts to demonstrate the secretion directly have not been successful.

The present edition extends to 267 octavo pages, exclusive of the biblio­graphy, which embraces 593 references. Although the work is mainly concerned with normal secretion of the urine, it contains valuable chapters on the action of diure~ics and other drugs, albuminuria, nephritis, and other renal disorders, and is almost equally interesting for physiologists and pathologists.