MANUAL OF OArrLE-FEEBING, 73 



have escaped resorption, and small portions of the diges- 

 tive fluids and of the worn-out mucous membrane of the in- 

 testines. In the herbi\ora they also generally contain all 

 the phosphoric acid coming from the metamorphosis of the 

 tissues of the body, while in the carnivora this substance 

 is excreted in the urine. The color of the excrements, as 

 ah'eady mentioned, is usually due to the portions of the 

 bile which have escaped resorption; when much green 

 fodder is eaten, its green coloring-matter (ehlorophyl) 

 passes unaltered into the fseces. 



The composition of tlie solid excrements varies 

 largely according to the feeding of the animal. 



It is seldom possible to attain a aomplete digestion of all 

 the nutrients of the food ; a certain portion almost always 

 escapes digestion, unless, perhaps, in the concentrated bye- 

 foddei^. 



The undigested portion is generally larger when a ricli 

 food is given, L e.^ when we strive for a rapid production 

 of organic substance, whether flesh, fat, or milk, than when 

 the fodder is just suflicient to maintain the animal. 



In the former case, too, the residues of digestive fluid 

 and of worn-out intestinal membrane are greater, owing 

 to the greater activity of these organs and the greater 

 quantity of Juices necessary to digest the richer and more 

 abundant fodder, so that from fattening or milk cattle we 

 get not only a utilization of fodder materials and conver- 

 sion of them into valuable products, but an increase in the 

 manurial value of the solid excrements, wliile in the case 

 of animals on maintenance-fodder the manure is the only 

 return for the fodder, and is of poorer quality than when 

 richer food is given. 



