Selected monographs.

Date:: 1888

Catalogue details

Licence: Public Domain Mark

Credit: Selected monographs. Source: Wellcome Collection.

40/440 (page 24)

solutions, sucli as the serum of tlio b]oo*d. Wo are therefore forced to assume that they also filter through the Malpighian tufts J but in an extremely minute quantity, corresponding with their small capacity for filtration. Let us then consider the epithelium somewhat more closely,, as to it is assigned the task of retaining the albumen. This- consists, after birth, of extremely flat, thin cells, which most closely resemble the endothelium of serous membranes. This epithelial investment,''^ says Cohnheim, is something quite peculiar to the glomerulus, having at the most a distant analogy with the endothelial membrane covering the choroid plexus, the seat of the secretion of the cerebro-spinal fluid,, which is almost free from albumen.^ If the analogy referred-to be real though distant, there is clearly one con- clusion to be drawn therefrom, and this is that the capillaries of the Bowman-Miiller's tufts permit the escape of a fluid almost, but not quite, free from, albumen. And we are the more justified in arriving at this conclusion, from the fact that it is in complete harmony with what we know regarding other normal transudations (and it may be added abnormal ones also) which pass through capillaries and epi- thelial membranes, and which all without exception contain large and varying quantities of albumen. Not merely does the cerebro-spinal fluid contain albumen, but the transuda- tions of all serous membranes which have an epithelial investment are albuminous, and normally so, as is evidenced especially by the pericardial fluid ; in the majority of the other sacs too little fluid is present for purposes of demonstra- tion. The aqueous humour which transudes in the anterior chamber of the eye, which has a complete epithelial covering, contains albumen, the perilymph and endolymph of the auditory labyrinth, which are certainly separated by epithe- lium from the secreting capillaries, contain albumen. Certainly all normal transudations (to say nothing of abnormal ones) contain albumen; in whatever part of the body fluid escapes from the blood tuithout the interposition of specific glandular epithelium, it contains albumen, even when it has to pass through an epithelial covering, as well as a capillary wall. It would therefore be marvellous if the This fluid contains albumen in tlie proportion of -3—3 per 1000.