THE COMPOSITION OF GRASSES. 



53 



cent of nitrogen present in the average albuminoid, and by sub- 

 tracting the sum of all these constituents from one hundred, the 

 percentage of undetermined matter is obtained, and as it of 

 course contains no nitrogen, and consists of the extractive ])rin- 

 ciples of the plant, it is described as 'Nitrogen free extract.' It 

 includes all the carbo-hj^drates, such a sugar, starch, and gum, 

 together Avith certain other allied substances, with which we are 

 less intimately acquainted, but which have a certain nutritive 

 value. 



Although it has been customary to state as albuminoids the 

 equivalent of the nitrogen found, this is rarely entirely correct, 

 as a portion is generally present in a less highly elaborated form 

 of a smaller nutritive value. This portion is described as non- 

 albuminoid nitrogen, and in analysis of the present day the 

 amount is always given as an additional source of information, 

 although our knowledge of its exact value to the animal is rather 

 uncertain. 



The wide variations in fiber and albuminoids must be regarded 

 as being entirely due to physiological causes, which are difficult to 

 explain. Digitaria sanguinale, for instance, which in one speci- 

 men contains the extreme amount of albuminoids and a small 

 amount of fiber has in another only half as much albumen and one 

 and three-quarter times as much fiber. We learn then, that 

 species are not in themselves at all fixed in their composition, 

 there being as large variations among specimens of the same as 

 between specimens of different species. 



Analysis of Phleuin pratcnse (Timothy) from vaiHous localities. 

 FULL BLOOM. 



