200 SPECIAL HISTOLOGY. 



seen it on one occasion in the Fowl) and other Mammalia, and 

 was not noticed by me in the cases of two executed criminals, 

 examined especially with respect to this point, whilst it is found 

 in Serpents, in the Salamander, Triton, Bombinator, Bufo, and is 

 very well marked in Fishes, and also, according to Remakes and 

 my own observations, in the Wolffian bodies, which have the 

 structure of kidneys, in the embryo of the Lizard ; in the last 

 two instances, they are also met with in the uriniferous ducts 

 at a greater distance from the Malpighian bodies. 



Of the very numerous pathological degenerations of the 

 tubuli uriniferi, I will notice only the following : The membrana 

 propria is frequently thickened to 0001, or even 0*002"', when 

 it often presents, on the inner aspect, very delicate, closely 

 approximated transverse strise. The epithelial cells, particu- 

 larly in the cortical substance, frequently contain oil-drops in 

 considerable quantity, so as often to present a deceptive resem- 

 blance to the cells of a fatty liver and at the same time, they 

 are usually enlarged to a diameter of 0-02"'. Together with the 

 oil, pigment granules (of the colouring matter of urine ?) 

 occur in them (also in the straight canals), whereas the con- 

 cretions of uric acid and calcareous salts, which are so fre- 

 quently met with in the canals of the tubules in the Vertebrata 

 have not as yet been demonstrated with certainty in the cells 

 themselves (in Fishes, Simon, l Thymus,' p. 69, often found crys- 

 tals in the renal cells) . Colloid-like, bright yellow masses are 

 frequent in the epithelial cells, which then most usually increase 

 in size, dilate into slender cysts as much as 0"05 — 0-072"' long, 

 and finally, by bursting, empty themselves of the colloid sub- 

 stance, whence the latter is found free in the uriniferous ducts 

 and also in the urine. A development of the epithelial cells 

 into other cysts, as is stated to take place by J. Simon and also 

 by Gildemeester (Tijdschr. d. Nederl. Maatsch. 1850) has not 

 yet occurred to my observation, whilst I have noticed, as did 

 Johnson, very distinctly, in an atrophied kidney, a partition of 

 the convoluted tubules into closed cysts, to all appearance by a 

 connective tissue developed between and constricting them. 

 These cysts had the same structure as the tubules and were 

 either of the same diameter, or distended into vesicles, 1'" 

 in width. The Malpighian bodies also may expand into 

 cysts, in which, together with a clear fluid, the atrophied 



