THE CHEMICAL COMPOSITION OF AMERICAN GRASSES. 



In submitting grasses to chemical analysis, with a view of judging of 

 their nutritive value, it is usual to determine the amount present of 

 water, ash, fat or oil, fiber and nitrogen. From the latter the amount of 

 albuminoids to which it is equivalent is readily calculated by multiply- 

 ing by a factor which represents the per cent, of nitrogen present in the 

 average albuminoid, and by subtracting the sum of all these constit- 

 uents from one hundred, the percentage of undetermined matter is ob- 

 tained, and as it of course contains no nitrogen, and consists of the ex- 

 tractive principles of the plant, it is described as Nitrogen free extract." 

 It includes all the carbo-hydrates, such as sugar, starch, and gum, to- 

 gether with certain other allied substances, with which we are less in- 

 timately 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 gener- 

 ally present in a less highly elaborated form of a smaller nutritive value. 

 This portion is described as non-albuminoid nitrogen, and in analyses 

 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 ultimate composition of the ash is also frequently determined, and 

 examples of the results obtained are of interest, as showing the mineral 

 matter that grasses withdraw from the soil. 



Without entering into a discussion of the nutritive value of the several 

 constituents of the grasses, for which reference can be made to Armsby's 

 Manual of Cattle Feeding, it is sufficient to say that during the past 

 few years the greater portion of the species described by Dr. Vasey in 

 the preceding portion of this bulletin have been analyzed, and the results 

 collected and rearranged, with some corrections, from the annual reports 

 of the Department are presented in the following pages. 



The first series consists of analyses made with specimens collected at 

 or near the time of blooming. Their origin is as follows: 



No. of anal. 



1. Paspalum laeve (Water grass). From Prof. S. B. Buckley, Austin, Tex. 1878. 

 2., Paspalum laeve (Water grass). From the Eastern Experiment Farm, West Grove, 

 Chester County, Pennsylvania. 1880, August 23-29. 



3. Paspalum ovatum. From S. L. Goodale, Saco, Me. 1880. 



4. Paspalum praecox. From Charles Mohr, Mobile, Ala. 1879. 



5. Digitaria fiUforme. From Charles Mohr, Mobile, Ala. 1878. 



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