Selected monographs.

Date:: 1888

Catalogue details

Licence: Public Domain Mark

Credit: Selected monographs. Source: Wellcome Collection.

44/440 (page 28)

led Heidenhain to assume that the epithelial covering of the glomerulus is an agent in the secretion of water, as 1 shall show further on. To facilitate the comprehension of what follows, I will now only observe, that according to my view, the assumption universally received and which forms the basis ot every theory, i.e. that the water of the urine is normally furnished only by the glomerular vessels, is thoroughly untenable, and that we ought rather to assume that the vessels in question supply only a portion, though certainly the larger portion, and that the remainder is yielded by the true secretory elements of the kidney, the epithelium of the uriniferous tubules. This last supposition is based upon the fact that we cannot imagine a glandular secretion without water, unless we picture to ourselves that the whole process consists in nothing else but fatty degeneration of the epithelium, as takes place for example in the formation of the sebaceous secretion of the skin. Nothing of this kind, however, can be thought of in connection with the kidney. Moreover, direct proof that these epithelial cells, i.e. those which invest the tubuli uriniferi, are actively engaged in the secretion of water, has been furnished by Nussbaum (32). The urinary water has therefore two sources, and is partly a transudation and partly a secretion. A firm grasp of this fact is an important aid in explaining the different changes which take place in the urine under various conditions. If therefore the fluid which escapes from the glomeruli be a transudation, is there any reason why it should form an exception to all other transudations, as regards the albuminous constituent which is a feature common to all ? Certainly the glomerular vessels are exceptional in this particular, that in them the lateral pressure is greater than in any other capillary system of the whole body. We know, however, that ceteris 'paribus, the quantity of albumen which filters through an animal membrane from an albuminous solution, increases with the increase of pressure, but not in a degree proportional thereto. And in fact this increase is an absolute one, and not relative in proportion to the total amount of the filtrate passing through in a certain unit of time, inasmuch as, with the augmented pressure, the degree of increase of the quantity of water which passes is