320 BOARD OF AGRICULTURE. 



the other important chissos of substances in feeding stuffs by the 

 fact tliiit the}' contain nitrogen. 



Such compounds as egg albumen, the muscuhir tissue of animals 

 and the caseine of milk are albuminoids, and to these animal sub- 

 stances the albuminoids of plants bear a close resemblance both in 

 chtmical i)roperties and in food value. The protein of feeding 

 stuffs cannot be directly determined with accuracv. The estimation 

 is an indirect one, and is based upon the fact that all albuminoids 

 contain approximately 16 per cent of nitrogen. If, therefore, the 

 percentage of nitrogen in any feeding stuff be multiplied by G.25, 

 the percentage of albuminoids is obtained with sufficient accuracy 

 for all practical purposes. The important and peculiar office which 

 albuminoids till in serving the uses of the animal kingdom is that 

 they constitute the only source of material for the formation of 

 muscular tissue, hair, horn, caseine, etc., etc. 



Plants contain otiier nitrogenous compounds called amides that 

 occur most abundantly in fodder and root crops, the amount varying 

 in the former at different periods of growth, while in the grains the 

 nitrogen exists almost wholly in the form of albuminoids. Fodder 

 tables generally give as the percentage of protein the product of the 

 total percentage of nitrogen b\' 6.25. 



A given amount of protein as stated for ha}' in tables of fodder 

 analyses is not quite the same thing, therefore, as the same amount 

 occurring in the grains, because in the former case much more of the 

 nitrogen belongs to the non-albuminoid, or amide form. 



The true value of amides in animal nutrition is not well defined. 

 That they are wholly like albuminoids in office seems hardly probable, 

 at least previous investigations do not show this. 



Crude fiber is the woody part of plants, and is that which remains 

 undissolved after treating vegetable substance with weak acids and 

 alkalies. Paper and cotton fiber are good examples of nearly pure 

 crude fiber. 



The nitrogen-free extractive matter includes all the non-nitrogenous 

 compounds of feeding stuffs, excepting crude fiber and the fats, the 

 most important and abundant members of this class being starch and 

 sugar. 



The fats or vegetable oils are extracted from plant substance by 

 ether, which also takes out more or less chlorophyl, wax, etc., es- 

 pecially' in the case of hays and coarse fodders. Olive, linseed and 

 cotton-seed oils are good examples of vegetable fats. 



