CHAPTER VIII 

 CONDITIONS INFLUENCING DIGESTION , 



The chemical changes and other phenomena consti- 

 tuting digestion, which have been described as occurring 

 in the ahmentary canal, are practically outside the con- 

 trol of the one who feeds the animals. They proceed in 

 accordance with fixed chemical and physiological laws. 

 It is, however, within the power of the feeder to so 

 manipulate the food or vary the conditions imder which 

 it is fed that the extent or completeness of digestion is 

 modified, and this must be regarded as an important 

 matter when we remember that only the digested food 

 is useful. 



181. Palatableness. — ^It is entirely reasonable to 

 believe that a thorough relish for food is conducive to 

 good digestion. The secretion of the digestive juices is 

 not a mechanical process, but is partly under the control 

 of the nervous system. With man, at least, the enjoy- 

 ment of eating, even its anticipation, stimulates the 

 secretory power of the salivary glands and those in the 

 mucous lining of the stomach, and it is evident that this 

 holds true with animals. Palatableness is, therefore, an 

 important factor in successful feeding, for it tends to pro- 

 mote a state of vigorous activity on the part of the diges- 

 tive organs. The experienced feeder knows well the 

 value of stimulating the appetite of his animals by means 

 of attractive mixtures. An agreeable flavor or taste adds 

 nothing to the energy or building-capacity of a food, but 



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