URINARY APPARATUS. 173 



of swelling and thus increase the consistency of the urine. 

 Acid horse urine is always less viscid than such as gives 

 an alkaline reaction because the epithelial cells swell more 

 in the former. 



All other domestic animals excrete a more watery urine. 



e. The specific gravity of urine is determined with an 

 araeometer, also called u r i n o m e t e r when specially con- 

 structed for this specific purpose. 



The specific gravity for the 



horse is 1020—1050, average 1040, 

 ox " 1025—1045, " 1030, 



dog " 1020—1060, " 1040. 



The specific gravity varies inversely with the quantity. 

 Aside from this an a b n o r m a 11 >• 1 o w specific gravity is 

 observed in diabetes insipidus (1001-1010) and in contracted 

 kidney. 



An a b n o r m a 1 1 y high specific gravity is observed in 

 all cases where the amount of urine secreted is below the 

 normal (fever) and in acute nephritis. High specific 

 gravity and increased quantity is observed 

 only in diabetes mellitus. 



B. Chemical Examination of the Urine. 



a. The reaction of the urine of healthy animals de- 

 pends on the kind of food: herbivora (horse, ox, sheep, goat) 

 secrete an alkaline urine, carnivora (dog. cat) secrete acid 

 urine. In omnivora the reaction depends altogether on the 

 food. 



In herbivora the alkaline reaction is due to the 

 presence of acid bicarbonate of lime CO3H — Ca — CO3H. 

 The organic acid salts of lime which are contained in the food 

 contain the acid radicles of malic, tartaric, succinic and lactic 

 acids. These latter, upon being absorbed into the blood, be- 

 come oxydized into acid carbonates which have an alkaline 

 reaction. 



In carnivora acid phosphates are the cause of the 



