Anatomical Changes. 1023 



lu calculating the time of development of the calculi their size and chemical 

 composition must be considered, and also the external conditions (Klimmer). Pflug 

 says that phosphatic concretions grow more rapidly than the other calculi. Eathke 

 observed in cattle in the space of three weeks the formation of calculi of from pin- 

 head- to bean-size. 



Anatomical Changes. Kidney stones are sometimes quite 

 small, covering the mucous membrane of the renal pelvis in 

 the form of fine or coarse grits, and are there mixed with the 

 urine, in exceptional cases they are imbedded in the renal 

 tissue; in other cases they are good-sized actual stones and 

 may fill out entire calyces and even the whole renal pelvis. 

 The last variety of stone is sometimes round, lying free in 

 the pelvis, or if present in numbers, they are polished smooth 

 by mutual friction. Larger stones show irregular coral shapes 

 with knobbed surfaces from having adapted their shape to 

 the form of the cavity in which they formed. Sometimes each 

 calyx is filled by one stone, in other cases the stones are con- 

 nected by their extremities which point toward the ureters 

 or they may fuse together to good-sized masses after atrophy 

 of the calyces. As the stones grow, the renal substance grad- 

 ually disappears and finally large stones may imitate the shape 

 of the kidney, and are found surrounded only by a thick 

 capsule. 



If several stones are present, the mucous membrane of 

 the renal pelvis is always inflamed, perhaps it contains hemor- 

 rhagic spots or ulcers, or is covered with diphtheritic pseudo- 

 membranes. The renal tissue usually bears the signs of an 

 acute or a chronic inflammation. 



The urinary calculi of herbivora are grayish-white, brown or mottled and con- 

 sist, according to examinations made by Fiirstenberg, largely of calcium carbonate 

 and magnesium carbonate which form multicolored layers around a nucleus consist- 

 ing of organic substances, rarely of calcium oxalate. In cattle and sheep the stones 

 are smooth, often small, yellowish or gray, spherical or angular, and have a peculiar 

 metallic or mother -of- {ivdd luster, which evidently is due to the very tine arrange- 

 ment of the layers, although Fiirstenberg believes it due to the admixture of ferrous 

 carbonate. Bourmer demonstrated 0.28% of iron in the renal stones of a cow. 

 (Some stones do not show layers and are more friable. They consist of a small 

 amount of organic material, of calcium carbonate and of a small quantity of mag- 

 nesia carbonate. In a cow which had probably suffered from leukemia or pseudo- 

 leukemia Joest found xanthin stones which usually are formed in case of consider- 

 al)le destruction of cellular nuclei and which had already been found by Weiske 

 in a ram having presumably suffered with leukemia. 



The calculi of carnivora contain ammoniacal magnesia phosphate and small 

 quantities of calcium phosphate or carbonate, usually also uric acid and its salts. 

 Cystin calculi are much less frequent and are always small, soft and of a greasy 

 luster. 



Symptoms. Renal calculi give rise to a clinical picture 

 which is as a whole similar to that of pyelitis, except that 

 the evidences of pain are more decided and are rarely absent. 

 Nevertheless cases undoubtedly occur in which large stones 

 are found on autopsy and perhaps total atrophy of one kidney, 

 and in which the animal showed no signs of disease during 

 life. The walk becomes stiff, the region of the kidneys sensi- 



