VI. 



MANURING AND GENERAL MANURES 



107 



resulting from waste of their tissue and the water drunk by them 

 which they have not exhaled as vapour from their lungs or skin. 



The chemical nature and the total quantity of the excreta depend 

 very largely upon the character and quantity of the food supplied. 

 This is especially true of the solid portion, which consists mainly of the 

 undigested matter of the food, but contains also certain products de- 

 rived from the digestive fluids, e.g., the bile and the pancreatic juice. 



The liquid portion of the excreta, on the other hand, consists 

 mainly of water, holding in solution substances produced by the wear 

 and tear of the muscles, etc., of the animal, these waste products being 

 separated from the blood stream of the animal by appropriate organs. 

 Of course these matters originally came from the food, but they are not 

 the immediate products, as are most of the constituents of the solid 

 excreta. 



Both the liquid and solid portions of the excreta contain large 

 quantities of substances of little or no value as fertilisers directly ; but, 

 inasmuch as they readily undergo putrefactive changes resulting in the 

 liberation of carbon dioxide and other gases, and the production of 

 bulky carbonaceous substances akin to humus in their nature, these 

 ingredients are of considerable importance in determining the effect of 

 farm- yard manure on land. 



The chemical character of the excreta produced on the farm, depends 

 upon a number of conditions the food, the breed of animals kept, their 

 age, whether fattening, working, or milking, and other circumstances. 



Obviously, if an animal is growing in size, or is yielding milk, its 

 food must contain much more of the important flesh-forming consti- 

 tuents than its excreta ; while in the case of an animal not increasing 

 in size nor providing milk, one might expect that the excreta would 

 contain practically all the matters contained in its food, with the ex- 

 ception of those consumed in respiration. Eemembering these facts, 

 it is not surprising to find, among published analyses of the excrements 

 of animals, considerable discrepancies. 



The following table gives the percentage amounts of the most 

 important manurial constituents of the excrements of the common 

 animals l : 



U.S. Dept. of Agriculture, Bulletin 15, 1893. 



