636 



PHYSIOLOGY OF THE DOMESTIC ANIMALS. 



phates, together with calcium phosphate, are deposited as a crystalline 

 precipitate. This process is known as ammoniacal fermentation, and is 

 due to the action of ferments derived from the atmosphere. In some 

 animals the urine always deposits mucus derived from the membranes 

 over which it passes. Its quantity is subject to great variations. 



The most important constituents of the urine are water, salts, gases, 

 and certain specific constituents. Among the salts, potassium com- 

 pounds are more abundant than sodium. Lime and magnesium are in 

 varying amounts. Of the acids H 2 SO 4 and P 2 6 are most abundant. 

 C0 2 in combination is found in the urine of the herbivora. When 

 NaCi forms part of the diet, this salt is also a large constituent of 

 urine. 



The following are the specific constituents of urine : 



1. The decomposition products of the albuminoids, as urea, uric 

 acid, hippuric acid, kreatin and kreatinin, and the combinations of 

 H 2 S0 4 with indol and phenol. 



2. Coloring matters, of which urobilin is the best known. 



3. Aromatic bodies which give the urine its peculiar odor. 

 The gases C0 2 , N, and O are found free in the urine. 



As regards quantitative composition there is great inconstancy. 



Water, . 

 Organic matter, 

 Inorganic matter, . 



Horse. 

 90. 

 5.5 

 4.5 



Ox. 

 91. 



5. 



4. 



Sheep. 



89. 



8. 



3. 



Hog. 



98. 

 0.5 

 1.5 



COMPOSITION OF THE URINE (BOUSSINGAULT). 



1000.0 1000.0 



(1) Diet of oats and clover-grass. 



(2) Diet of hay and potatoes. 



(3) Diet of cooked potatoes. 



1000.0 



The water, K, Na, Ca, and Mg compounds are derived directly 

 from the blood, and in greater part directly from the food and drink, and 

 in fasting animals from waste of tissues. H 2 SO 4 originates in oxidation 

 of the sulphur compounds in food ; the phosphates from the oxidation 

 of albuminoids of food and tissues ; carbonates, partly directly from 



