Selected monographs.

Date:: 1888

Catalogue details

Licence: Public Domain Mark

Credit: Selected monographs. Source: Wellcome Collection.

39/440 (page 23)

the slight diffusibility and capacity for filtration of albumen, this must, at least to some extent be waived, masmuch as membranes,permeable by albumen, are to be found throughout the body. On the other hand, quite recently the belief has arisen that the escape of albumen from the Malpighian tuft- is prevented by the epithelial investment of the vessels ; and this theory is now acquiesced in by all those who endeavour to explain the absence of albumen in the fluid which leaves the tuft, this view being adopted especially by Runeberg, Heidenhain, and Oohnheim, as already mentioned.^ Nothing could appear more simple and intelligible than this explana- tion, and it might be adopted forthwith if it could relieve us of any one difficulty, and did not too obviously contradict patent facts. In the first place, it contradicts the well- known fact, insisted upon always, except only upon this occasion, that egg-albumen passes without difficulty into the urine, and, as has been shown by Nussbaum on frogs, and Ribbert on rabbits, through the vessels of the Malpighian tufts. The explanation for this is sought for in the greater ease with which egg-albumen passes through a filter, an explana- tion to which as yet no one has raised any objection, and the same will apply to peptone. This marked capacity for filtra- tion has been incidentally shown on dead animal membranes. It is obvious that, when with regard to these cells, it is only a question of a greater or less capacity for filtration, it is impossible to understand how they can be completely im- permeable for the normal albuminous constituents of the blood. For there is no doubt whatever that these albuminous substances are capable of filtration, especially from saline ^ A different view is adopted by Eibbert in bis recent work on ' Nepbritis and Albuminuiia' (29). He attributes no importance in tbis respect to tbe • epitbelial covering of tbe Malpigbian tufts, but thinks tbat these capil- laries, whicb, according to b.im, are almost entirely without nuclei, possess more cohesion than other capillaries, and therefore prevent the escape of albumen. It is hardly possible to take this view even if we choose to . admit as correct Eibbert's isolated assertion with regard to tbe paucity of nuclei of those capillaries. There are, moreover, no capillaries which are impermeable by albumen, and experiments made with this view on kidneys both before and after death have demonstrated that there is no difference be- tween these and other organs in this respect; and, lastly, the investigations • of Fromraann and of Riemer on argyria have shown that solutions of silver pass as readily through the Malpigbian tu Cts as through any other vessel (30/.