DISEASES OF THE URINARY ORGANS. 163 



its elements, and thus to favor its crumbling and expulsion. This is a 

 principle which must never be lost sight of in the treatment of calculi : 

 The immersion of the stone in a liquid of a lower specific gravity than 

 that in which it has formed and grown tends to dissolve out the more 

 soluble of its component parts, and thus to destroy its density and 

 cohesion at all points, and thereby to favor its complete disintegration 

 and expulsion. This explains why cattle taken from a herd on our 

 magncsian limestone in spring, after the long dry feeding of winter, 

 usually furnish renal calculi, while cattle from the same herd in the 

 fall, after a summer's run on a succulent pasture, are almost aways free 

 from concretions. The abundance of liquid taken in the green food and 

 expelled through the kidneys and the low density or watery nature of 

 the urine have so opened the texture and destroyed the density of the 

 smaller stones and gravel that they have all been disintegrated and 

 red. This, too, is the main reason why benefit is derived from 

 a prolonged stay at mineral springs by the human victims of gravel. 

 If they had swallowed the same number of quarts of pure water at 

 home, and distributed it at suitable intervals over each day, they 

 would have benefited largely without a visit to the springs. 



It follows from what has been just said that a succulent diet, includ- 

 ing a large amount of water (gruels, sloppy mashes, turnips, beets, 

 potatoes, apples, pumpkins, ensilage, succulent grasses), is an impor- 

 tant factor in the relief of the milder forms of stone and gravel. 



Prevention of calculus especially demands this supply of water and 

 v. at cry rations on all soils and in all conditions in which there is a 

 predisposition to this disease. It must also be sought by attempts to 

 obviate all those conditions mentioned above as causative of the malady. 

 Sometimes good rainwater can be furnished in limestone districts-, but 

 putrid or bad smelling rainwater is to be avoided as probably more 

 injurious than that from the limestone. Unsuccessful attempts have 

 ben made to dissolve calculi by alkaline salts aud mineral acids respect- 

 ively, but their failure as a remedy does not neressarity condemn them 

 as preventives. One dram of caustic potash or of hydrochloric acid 

 maybe given daily in the drinking water. In diametrically' opposite 

 ways these attack and decompose the less soluble salts and form new 

 ones which are more soluble and therefore little disposed to precipitate 

 in the solid form. Hoth are beneficial as increasing the secretion of 

 urine. In cases where the diet has been too highly charged with phos- 

 phate* (wheat bran, etc.), these aliments must be restricted and water 

 allowed ad libitum. Where the crystals passed with the urine are tho 

 sharp angular (octahedral) ones of oxalato of lime, then the breathing 

 should be made more active by exercise, aud any disease of the lungs 

 Kiibj<!cted to appropriate treatment. If the crystals are triangular 

 prisms of ammonia magnesium phosphate or star-like forms with feathery 

 rays, the indications are to withhold the food or water that abounds in 

 magnesia and cheek the fermentation in the urine by attempts to destroy 



