104 THE CHEMISTEY OF THE FAKM. 



The diminution in digestibility with the increasing 

 maturity of the grass is very striking, and is very equally 

 spread over all the constituents. Experiments with clover 

 cut at different stages of growth have yielded similar 

 results. 



It follows from what has now been stated that no fixed 

 nutritive value can be ascribed to fodder crops, or to the 

 hay made from them, as both their composition and 

 digestibility are largely influenced by their age and 

 condition when cut. The young plant is always the most 

 nutritive. The superior fattening quality of a pasture, 

 as compared with that of the hay made from it, is clearly 

 due to the fact that on land continuously grazed the 

 animal is entirely fed on young herbage, while hay 

 will always consist of the fully grown plant. Fur- 

 ther illustrations of the different digestibility of hay 

 of various qualities have been already given on page 

 100. 



Fodder crops do not sensibly diminish in digestibility 

 by being made into hay, if haymaking is carefully carried 

 out in good weather. But the loss of the finer parts of 

 the plant by rough treatment, or the washing out of 

 soluble matter by rain, may considerably diminish the 

 digestibility. Hay appears to lose some of its digesti- 

 bility by keeping. 



Influence of one food on the digestion of another. 

 If to a diet of hay and straw, consumed by a ruminant 

 animal, a pure albuminoid, as wheat gluten, be added, 

 the added food is entirely digested without the rate of 

 digestion of the original food being sensibly altered. 

 The same result has been obtained in experiments 

 with pigs fed on potato s, to which variable quantities 



