246 ANNUAL REPORT OF NEW- YORK 



no doubt that this method of finding the nutritive matter of the 

 plants afforded data which could not fail to be of value to the 

 intelligent agriculturist, and that it was the best which the state 

 of science at that time could offer, or which with a moderate 

 outlay of labor, was possible, is sufficiently guaranteed by the 

 name of the great chemist who suggested it. 



" But chemistry and physiology have made gigantic strides since 

 that time. We have learnt to separate and identify the chemical 

 principles, of which plants are made up, and their composition 

 and properties have been intimately studied. Physiology, on the 

 other hand, has taught us to a considerable extent the part which 

 these principles play in the nutrition of animals. It has shown 

 us that from one is formed flesh, from another fat, whilst to 

 others, again, is allotted the office of supporting respiration and 

 producing animal heat. It is not meant that science was 

 entirely at fault on these points at the period in question, but 

 there can be no doubt that the greater part of our present know- 

 ledge of the subject is of much later date. 



* * * It has long been evident to all who have paid any 

 attention to these subjects, that Mr. Sinclair's determinations of 

 nutritive equivalents for different grasses, however valuable they 

 were at the time they were executed, are quite unsuitable to our 

 present more advanced stage of knowledge. 



" It may be shortly stated that modern chemistry has divided 

 the principles of plants into two great classes — the one including 

 all those vegetable principles which contain nitrogen^ the other 

 comprising those which are destitute of this element. * # * 



# * cc rpj^g pj^jj adopted by Mr. Sinclair for the determina- 

 tion of the nutritive properties of the grasses, was defective in 

 more ways than one. In the first place, it afforded no kind of 

 information as to the relative quantity of flesh-forming, fatten- 

 ing, and heat-producing compounds existing in the plants; and in 

 the second, it did not even give a correct idea of the proportion 

 of all these substances taken collectively — since, with our present 

 knowledge of the properties of the nitrogenous principles, we 

 cannot doubt that treatment with hot water would fail to extract 

 the most nutritive portions of the grass. 



"As a supplement to Mr. Sinclair's excellent work, and a subject 

 not unworthy of considerable labor, it seemed desirable to exam- 



