136 DISEASES OF CATTLE. 



Other conditions, however, enter hug-ely into the causation of 

 stone, or gravel. A high density of urine resulting from a highly 

 saturated condition is often present for a length of time without 

 any precipitation of solid materials. Urea and carbonates may be 

 present in excess, the food may be given dry, and drinking water 

 may be deficient in amount without any deposition of stone or 

 gravel. The presence of noncrystalline organic matter in the urine 

 becomes in such cases an exciting cavise. Rainey 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 pow^erful, 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, gene- 

 rating excess of mucus or pus; inflammation of the kidneys, causing 

 the discharge into tlie urinary passages of blood, albumin, or hya- 

 line casts; 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 will almost 

 infallibly 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 



