PATHOLOGICAL STATES OF THE KIDNEY. 549 



latter appears, and the tubuli become rapidly longer and convoluted. 

 The Malpighian bodies are originally merely the solid thickened 

 extremities of the tubuli, the interior cells of which subsequently 

 become the capillary coil. In the new-born infant, the tubuli are 

 one-third as large as in the adult, and the whole kidney one-half as 

 large. (Harting.) Therefore no tubules are formed after birth. 



The suprarenal glands will be described in connection with the 

 blood- vascular glands (p. 592), since they appear to have no phy- 

 siological connection with the kidneys. 



Pathological States of the Kidney. 



1. The epithelial cells may contain abnormal contents; e. g. an 

 increased amount of fat-drops, constituting fatty degeneration of the 

 kidney (p. 310, 4), with or without pigment-granules; also colloid- 

 like bright-yellow masses are sometimes found in the cells, when 

 they generally dilate into slender cysts, oj^ to T 4o- of an inch long, 

 and which at length burst and discharge the colloid substance into 

 the tubuli, and then into the urine. Cysts may also be formed by 

 partitions of the tubuli contorti, finally separating their extremities 

 from the portions below in the pyramids. The epithelial cells be- 

 come detached in acute desquamative nephritis. 



2. The basement-membrane sometimes becomes much thickened 

 0* TsJoF.t goVtf of an inch), and presents close transverse strias 

 on its inner surface. 



3. The Malpighian bodies may expand into cysts containing the 

 atrophied glomerulus and a clear fluid. 



4. As abnormal contents (p. 215), the tubuli may contain blood, 

 fibrine, the colloid substance before mentioned, concretions in the 

 straight tubuli, principally of carbonate and phosphate of lime; and 

 of uric acid salts, in the new-born infant, giving the pyramids a bril 

 liant gold-yellow color. In Bright's disease, exudations into the 

 tubuli first remove the epithelium, after which they become atro- 

 phied, or altogether disappear; or become filled with a fatty broken - 

 up exudation, and dilated into minute nodosities or granulations. 



5. In inflammation of the kidney, the stroma often becomes so 

 much condensed by the exudation as more or less to compress the 

 tubuli. Often, also, the exudation becomes organized into embry- 



Fig. 379. 



A. Uriniferous tube containing a homogeneous cast. 



