134 DISEASES OF CATTLE. 



uny precipitation of solid materials. Urea and carbonates may be 

 I^resent in excess, the feed may be given dry, and di'inking water 

 may be deficient in quantity without any deposition of stone or 

 gravel. In such cases, the presence of noncrystalline organic matter 

 in the urine becomes an exciting cause. Eainey and Ord have 

 shown experimentally that colloid (noncrystallizable) bodies like 

 mucus, epithelial cells, albumin, pus, blood, hyaline casts of the 

 kidney tubes, etc., not only determine the precipitation of crystal- 

 lizable salts from a strong solution, but they determine the precipi- 

 tation in the form of globular masses, or minute spheres, which, 

 by further similar accessions, become stones, or calculi, of various 

 sizes. The salts that are deposited by mere chemical reaction with- 

 out the intervention of colloids appear in the form of sharply defined 

 angular crystals, and hence the rough, jagged crystals of oxalate of 

 lime or ammonia-magnesium phosphate. Heat intensifies the action 

 of the colloids in causing precipitation of the dissolved salts, so that 

 the temperature of the kidneys and bladder constitute favorable 

 conditions. Colloids that are undergoing decomposition are also 

 specially powerful, so that the presence of bacteria or fungi causing 

 fermentation is an important factor. 



In looking, therefore, for the immediate causes of urinary calculi 

 we must accord a high place to all those conditions which determine 

 the presence of excess of mucus, albumin, pus, blood, kidney casts, 

 blood-coloring matter, etc., in the urine. A catarrhal inflammation 

 of the pelvis of the kidney, of the ureter, or of the bladder, generat- 

 ing excess of mucus or pus; inflammation of the kidnej^s, causing 

 the discharge of blood, albumin, or hyaline casts into the urinary 

 passages; inflammation of the liver, lungs, or other distant organ, 

 resulting in the escape of albumin in the urine; disorders of the 

 liver or of the blood-forming functions, resulting in hematuria or 

 hemoglobinuria; sprains or other injuries to the back, or disease 

 of the spinal marrow, which cause the escape of blood with the 

 urine; the presence in the bladder of a bacterial ferment, which 

 determines the decomposition of the mucus and urea, the evolution 

 of ammonia and the consequent destruction of the protecting cel- 

 lular (epithelia) lining of the bladder, or the irritation caused by 

 the presence of an already formed calculus, may produce the colloid 

 or uncrystallizable body that proves so effective in the precipitation 

 of stone or gravel. It has long been known that calculi almost in- 

 variably form around any foreign body introduced into the kidney 

 or bladder, and I have seen a large, calculous mass surrounding a 

 splinter of an arrow that had penetrated and broken off in the body 

 of a deer. The explanation is now satisfactory — the foreign body 

 carries in with it bacteria, which act as ferments upon the urine 



