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 substractiug the sum of all these constitu- 

 ents 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 equiva- 

 lent of the nitrogen found, this is rarely entity 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 

 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 min- 

 eral 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 Arinsby'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 tins Bulletin have been analyzed, and the results 

 collected and re-arranged, 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. raapalum laive (Water Grass). From Prof. S. B. Buckley, Austin, Tex. 1878. 



2. Paspalum hv.vc (Water Grass). From the Easte.rn Experimental Farm, West 



Grove, Chester County, Pa. 1880, August 23-29. 



3. Paspaluin dilatatum. From S. L. Goodale, Saco, Me. 1880. 



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



