466 URO-GENITAL SYSTEM. 



ing a prolonged contact with the walls of the tubes. In the 

 second place, the lining epithelium throughout the principal 

 part of these tubes is clear and transparent, unlike the gran- 

 ular epithelium of the secreting glandular sacs; 1 and more- 

 over, whilst this latter reveals its function by the numerous 

 cellular detritus that are found in the secreted liquid (since 

 in a general way it may be stated that every secretion of this 

 kind is the result of a desquamated epithelial moulting) ; on 

 the contrary, the epithelium of the uriniferous tubes shows 

 little if any of this detritus, the urine being a liquid which is 

 very poor in globular elements. This epithelium thus appears 

 destined to preside over an absorption, and undoubtedly does 

 so in an active manner, by removing from the serum an ele- 

 ment so essential to the organism, and of which the blood can- 

 not be deprived without risk, viz. albumen. Should this 

 epithelium become diseased, it will no longer fulfil its func- 

 tion, and albumen will not be absorbed, but will appear in 

 the urine; this latter accident occurs in Bright's disease, 

 which is precisely a disease of the kidney epithelium. Those 

 writers who would allow for this epithelium a function of 

 secretion, by means of which the wall of the tube would add 

 to the filtered water the constituent elements of urine, find 

 themselves in face of a singular contradiction when they 

 desire to explain the pathogeny of albuminuria; because, as 

 a necessary result of their theory, when this epithelium is 

 diseased, it must secrete, not only the solid matters which 

 normally belong to the constitution of urine, but in addition 

 to these a new element, albumen : thus we should have, as 

 the sole example in the organism, this epithelium performing 

 its function with more activity in a diseased than in a normal 

 state; producing all the elements belonging to its normal 

 condition, and others besides. 2 



We know already that a feeble pressure in the blood- 

 vessels conduces to a favorable absorption (see p. 273). We 

 have also seen that in the capillaries which are near the uri- 

 niferous tubes the pressure is less than in the ordinary capil- 

 laries. The interstitial network of blood-vessels is then 



1 See the note on p. 533. 



2 These considerations of pathology, which belong to the theory 

 of urinary secretion, as we have just evolved, have been lately de- 

 veloped, especially in relation to albuminuria, in a thesis by G. 

 Fayet: " Essai sur la Pathogenic de 1' Albuminurie. " Montpellier, 

 1872. See, also, J. B. Olinger, " Esquisse de la Physiologic de la 

 Fonction Urinaire." Paris, 1873, No. 84. 



