KIDNEY. 



[ 376 ] 



KONDYLOSTOMA. 



In the Mammalia generally the structure 

 of the kidneys agrees essentially with that of 

 man. 



In the lower Vertebrata they exhibit dif- 

 ferences which relate principally to the fol- 

 lowing particulars : 1, the form, which in 

 birds, fishes, and reptiles is considerably 

 more elongated and frequently flattened; 

 2, the tabulation, which in the human adult 

 kidney is indistinct, although marked in the 

 foetus, whilst in that of other Vertebrata the 

 separate lobules are very distinct, sometimes 

 being connected only by the branches of the 

 ureter; 3, the Malpighian tufts, which in 

 birds, reptiles, and fishes consist of a single 

 convoluted vessel, and which in some (naked 

 reptiles) are larger, in others (osseous fishes) 

 smaller than in man ; whilst in birds (also 

 the sheep) they have been found inserted 

 into the sides of the tubules ; and 4, in the 

 structure and arrangement of the urinary 

 tubules; these are uniform in size in fishes; 

 furnished with ciliated epithelium in the 

 reptiles and fishes, and present varieties in 

 regard to the convolution, branching, and 

 termination in the ureter. 



The epithelial cells of the urinary tubules 

 are not unfrequently found to contain the 

 ordinary urinary deposits, which are more 

 often still met with in the cavities of the 

 tubules. Many of these are probably, how- 

 ever, formed after death (see URINARY DE- 

 POSITS). 



Among the morbid changes of the kidney, 

 passing over cancer, tubercle, variations in 

 the degree of vascularity, the presence of 

 calculi, and the ordinary products of inflam- 

 mation, may be mentioned the occurrence 

 of cysts. These are met with of various 

 size and in variable number. They may 

 contain a serous liquid, a yellowish colloid 

 substance, or a consistent albuminous mat- 

 ter with concentric bodies, and may occur in 

 a kidney otherwise healthy, or when affected 

 with Bright's disease. The walls of the 

 cysts do not differ in structure from those of 

 the tubules, except in being thickened; they 

 have been accounted for as arising from 

 dilatation of the tubules or Malpighian cap- 

 sules, in consequence of obstruction to the 

 escape of the urine, distension of the epi- 

 thelial cells of the tubules, and degeneration 

 of their nuclei, forming colloid cells. The 

 first is probably the general cause, and cer- 

 tainly an occasional one, the Malpighian 

 tufts having been found within the enlarged 

 cysts after injection. Sometimes the cysts 

 are those of Echinococci. In Bright's kid- 



ney the tubules are found deprived of their 

 epithelium, the cells filled with albuminous, 

 fibrinous, or fatty matter ; in the advanced 

 stage both becoming undistinguishable in 

 some parts, whilst in others cells and tubules 

 are loaded with fatty globules, producing 

 the well-known granular appearance. 



In examining the structure of the kidney, 

 sections must be made with a Valentin's 

 knife. The arrangement of the vessels may 

 be shown by injection, and the injected pre- 

 parations are very beautiful, and form ge- 

 neral favourites. The Malpighian bodies 

 are readily filled, the injection being thrown 

 into the artery, and they are readily recog- 

 nized by their resemblance to little apples 

 upon the branches of a tree, or bunches of 

 currants. The injection should be red. If 

 the injection be coarse, it will burst through 

 the capillaries of the tufts, and partially fill 

 the tubules, as in fig. 388 p ; but if it be 

 fine, it will fill the venous plexus. The uri- 

 nary tubules should be injected from the 

 ureter, white (lead) injection being used ; 

 and considerable force is required to make a 

 good injection, but this must be very gradu- 

 ally applied. PI. 1. fig. 35 is intended to 

 represent a portion of a kidney of a pig. 

 The kidneys of the smaller and lower ani- 

 mals are best injected from the heart. 



BIBL. Kolliker, Mikrosk. Anat. ii. and 

 the Bibl. therein ; Bowman, Phil. Trans. 

 1842 ; Johnson, Todd's Cyclopaedia of Anat. 

 and Phys., art. Ren. ; Toynbee, Med. Chi. 

 Trans, xxx. ; Siebold and Stannius, Ver- 

 gleichend. Anat. ; Forster, Handb. d. Path. 

 Anat.; Frerichs, Die Brightsche Nierenkrank- 

 heit, 8fc. ; Gairdner, Edinb. Monthly Journal, 

 viii. 



KNIFE, VALENTIN'S. INTRODUC- 

 TION, p. 23. 



KOLPODA. SeeCoLFODA. We omitted 

 to state, under the latter head, that Du- 

 jardin places this genus in his family Para- 

 mecia. 



KONDYLOSTOMA, Duj. A genus of 

 Infusoria, of the family Bursarina. 



Char. Body elongated, cylindrical, or 

 fusiform, slightly arcuate, the ends obtuse 

 and depressed, with a very large mouth 

 margined with stout cilia, and situated late- 

 rally at the anterior end ; surface obliquely 

 striated and ciliated. 



K. patens (PI. 24. fig. 31 ; fig. 32, slightly 

 compressed). This appears to be the same 

 animal as Oxytricha caudata, E. It has a 

 moniliform nucleus. Marine. 



BIBL. Dujardin, Infus. p. 516. 



