150 THE CHEMISTRY OF THE FAQM 



however, a very abundant and rich diet the proportion 

 digested may be seriously diminished. 



The influence of labour on digestion is inconsider- 

 able. The mean of Grandeau and Leclerc's numerous 

 experiments on Paris cab horses was as follows : — 



Fond Digested. 



At rest 1,000 



Walking exercise 1,032 



At work walking 1,007 



Trotting 976 



At work trotting 973 



At work in cab . . 959 



The cooking of food is generally of doubtful advan- 

 tage ; beans, maize, and bran are not better digested 

 by horse or ox when previously soaked in water. 

 Barley, maize, and pea meal have been found more 

 nourishing for pigs when given dry than when pre- 

 viously cooked. When food has been treated with 

 boiling water the digestibility of the albuminoids is 

 distinctly diminished. 



Differences in the quality of a food may exercise a 

 great influence on its digestibility ; the addition of 

 another food may also considerably alter the rate of 

 digestion of the first food. 



The digestibility of fodder plants is mainly deter- 

 mined by their age; all the constituents of a young 

 plant are more digestible than in the same plant of 

 greater age. The composition of meadow grass cut at 

 three different dates has been already given on page 

 138 ; the three cuttings were supplied to sheep in the 

 form of hay, and the following digestion coefficients 

 were obtained : — 



