366 Mr. E. N. Horsford on the Value 



found in the animal kingdom, gave the above fact its expla- 

 nation. 



The food must contain an ingredient suited to replace the 

 animal matter consumed. 



This being known, and the quantitative relation of the se- 

 veral elements of the nitrogenous compounds being also known, 

 an estimate of the value of given kinds of food becomes, in the 

 hands of the chemist, a problem of comparatively easy solu- 

 tion. 



The following investigation, undertaken at the suggestion 

 and under the direction of Prof, von Liebig in the Giessen la- 

 boratory, had for its object the determination of the relative 

 values of the different kinds of vegetable food. These values 

 are threefold. 



The various forms of food derived from grains, herbage and 

 roots, furnish — ], bodies containing nitrogen; 2, bodies desti- 

 tute of nitrogen; and 3, inorganic salts, all of which are ser- 

 viceable in the animal ceconomy. 



The nitrogenous bodies, from their solution in the blood, 

 form the tissues — the actual organism. .The bodies wanting 

 nitrogen contribute, by their more or less perfect combustion, 

 to the warmth of the animal body ; and the salts of the alkalies 

 and alkaline earths serve in building up the osseous frame- 

 work, beside constituting an essential part of every organ of 

 the animal system. 



Their values for the latter purpose are in general in pro- 

 portion to the phosphates their ashes contain. 



Their values for the second purpose may be considered in 

 general as in the inverted relation of their values for the first, 

 or inversely proportioned to the per-centage of nitrogen. 



Their values for the first purpose, that of ministering to the 

 support and growth of organic tissues, have been the specific 

 object of the hereafter enumerated determinations. 



Boussingault,to whom the agriculturist is so largely indebted 

 for investigations bearing upon the interests of husbandry, 

 has not left this field untrodden. It was thought, however, 

 that the worth of his table of nutrition could lose nothing by 

 a series of carefully conducted. analyses, having the same ob- 

 ject in view. It was moreover conceived, that in substances 

 containing so small a per-centage of nitrogen as grains and 

 roots generally, the method of Messrs. Varrentrapp and Will 

 for determining nitrogen would give more accurate results 

 than that of Dumas employed by Boussingault. The analyses 

 hereafter given of the same substance, rarely varied from each 

 other more than one-tenth of one per cent : and yet in ge- 

 neral the determinations which follow, and those of similar 



