SILOS, EXSILAGE AKD SILAGE. 21 



the intestines of most animals in a great measure un- 

 changed. Thus, animals which thrive on the young 

 shoots of early spring, can with difficulty sustain them- 

 selves on the more matured branches of the advancing 

 summer. The reason of this difference is, that the 

 starch and gum, and similar soluble and digestible sub- 

 stances of which the young shoot consists, are gradually 

 changed into the insoluble and, in general, almost indi- 

 gestible woody fibre of which the stem and branches of 

 the mature plant are in great part composed. 



" When green grass or clover, approaching to maturity, 

 is first cut down, it contains a considerable proportion 

 of starch, sugar, and gum, still unchanged into woody 

 fibre, as it would mostly be were the plant allowed to 

 become fully ripe. But when left to dry in the open 

 air, the circulation proceeds to a certain extent, and, 

 under the influence of light, woody fibre continues to be 

 formed in the upper part of each stem, until it becomes 

 completely dry. It may even be a matter of doubt 

 whether this process of change does not often proceed 

 after the hay has been carried off the field and stacked. 



" The effect of this change will obviously be to render 

 the dry hay less digestible, on the whole, and, conse- 

 quently, less valuable as food, than the green grass from 

 which it was prepared. 



66 Again, we know that by drying, many very digestible 

 and nourishing substances become less soluble, and con- 

 sequently, more difficult of digestion. The stomach of 

 a growing animal cannot afford the time necessary to 

 the complete digestion of such dry substances, and 

 hence a larger portion of the really nutritive matter of 

 their food is rejected in the droppings of animals which 

 are fed upon them. How much of dry corn escapes, 

 half digested, from the stomach of the horse, how 

 much, probably, of the animal matter of the bones it 

 eats, from the stomach of the dog, which either of 



