DISEASES OF THE URIWARY ORGANS. 4(37 



and particularly careful not to scratch the parts with the finger nails. If 

 this occurs the yard may swell to enormous proportions ; if so, bathe ii 

 with warm water and suspend it in a mde bandage passed over the loins. 

 Repeat the bathing two or three times a day. Give gentle exercise ; and 

 when the swelling is nearly gone, oil it with olive oil. 



XV. Urinary Calculi. 



Stones or calculi in the urinary apparatus differ in size, chemical com- 

 position and location. Sometimes they attain to very large sizes ; some- 

 times several small ones exist in the same place, and sometimes the 

 deposit is sand-like, the granules not uniting to form a stone. 



Their chemical composition differs according to the nature of the food. 

 The calculi of herbivorous or grazing animals are composed mostly of the 

 carbonates, while those of carnivoi-ous or flesh eating animals consist 

 mainly of the phosphates. The calculi of omnivorous animals partake of 

 the character of the two kinds just mentioned. They will be more largolv 

 composed of the carbonates or of the phosphates according to the cha'-ac- 

 ter of the food and water taken. 



Causes. — The carbonates of lime and magnesia are the principal com- 

 ponents of the calculi of horses and cattle ; they are due to the large 

 proportion of vegetabje acids in the food. These vegetable acids become 

 transformed into carbonic acid, which unites with the lime and magnesia 

 •n the blood, thus forming calculi. The tendencies to form calculi from 

 the food are strengthened by the following accessory causes : Scarcity 

 of water ; disinclination to drink ; excessive loss of water from the sys- 

 tem by diarrhoea and dysentery or profuse sweating ; feverish conditions, 

 giving rise to scanty secretions of urine ; dry winter fodder; and hard 

 drinking water. 



A solid substance of some kind for a nucleus or starting point is usually 

 necessary to their formation ; around this nucleus the salts crystallize in 

 concentric layers. The nucleus may be a particle of mucus, fibrine 

 or blood, or a foreign body introduced with the catheter. 



The locations in which they may be found are the kidneys, ureters (the 

 tubes leading to the bladder), the bladder, the urethra and the fossa of the 

 glans penis. 



How to know it. — Those in the kidneys and ureters cause colicky pains, 

 straddling gait, tender loins, and sometimes blood in the urine. Those in 

 the ureters can sometimes be felt by the hand introduced into the rectum. 



Those in the bladder get into the passage and obstruct the urine occa- 

 sionally, in which case they give rise to frequent straining efforts to pass 

 urine ; the urine escapes in driblets and jets, with frequent sudden ariests 

 of the flow ; but if the stone does not get into the passage, the flow is not 



