DIGESTION BY RUMINANTS 145 



the differences are, however, exaggerated in animal 

 experiments, from the circumstances mentioned in the 

 previous note (p. 142). Amides, being soluble bodies, 

 have been usually reckoned as digestible albumin. 



Of the fibre in hay and straw, about 45 — 60 per 

 cent, is generally digested by ruminant animals. The 

 fibre of leguminous hay and straw (clover and lucerne 

 hay, and bean straw) is less digestible than the fibre 

 of similar gramineous foods (grass hay, oat and wheat 

 straw). It has been shown that, both in the case of 

 the soluble carbohydrates and of the fibre, the portion 

 left undigested is much richer in carbon than the 

 portion digested. It appears, therefore, that while 

 cellulose is digested to a considerable extent, the lignin 

 which' forms in the tissues as the plant increases 

 in age, and which contains a larger proportion of 

 carbon, is much less digestible. Chemical analysis 

 also shows that the fibre of leguminous hay and straw 

 is richer in carbon, and consequently in lignin, than 

 the fibre of grass hay or cereal straw. 



The concentrated foods placed in the lower section 

 of the table are seen to be far more thoroughly digested 

 than is the case with hay or straw. When of good 

 quality, 80 — 90 per cent, of the organic matter of 

 these foods will be assimilated by the animal, except 

 in those cases where much fibre is present. The 

 albuminoids and fats in these foods have especially a 

 greater digestibility than the same ingredients in hay 

 and straw. The amount of fibre is usually too small 

 for its digestibility to be determined with certainty. 

 The hard fibre forming the husk of seeds is apparently 

 but little digested. 



The undigested albuminoids of food have a different 

 10 



