NUTRITIVE EQUIVALENTS. 235 



A line of investigation, both scientific and practical, 

 equally interesting and valuable with the foregoing, 

 would lead into the comparative nutritive equivalents 

 of hay and other feeding substances. This is not the 

 place to discuss that subject in full, the line of our pres- 

 ent inquiry embracing only the comparative nutritive 

 values of the grasses themselves. For convenience of 

 reference, however, I subjoin the following Table (XII.), 

 embracing the results of the profoundest researches of 

 many distinguished chemists and practical men, both in 

 the laboratory and the barn. Boussingault and others, in 

 Prance, and Fresenius, Thaer, and others, in Germany, 

 have devoted to these and similar investigations the 

 best part of their lives. . 



It is necessary to remark that tables of nutritive 

 equivalents are liable to imperfections, on account of 

 sources of error which must exist in the nature of 

 things, as difference of soil, climate, season, imperfec- 

 tion of methods of analyses, &c. ; but, making all allow- 

 ance for these, and admitting that the table cannot be 

 absolutely and literally correct or perfect, it possesses 

 great practical value and interest, as giving a good gen- 

 eral idea of the relative value for feeding purposes of 

 various agricultural products. 



In regard to the nutritive value, as based on the 

 amount of nitrogen or nitrogenous compounds, it may 

 be remarked that the latest and most careful experi- 

 ments, conducted by most experienced and competent 

 experimenters, tend to show that this basis is correct, 

 so far as it can be applied to substances so analogous 

 in composition that they can be included in one group ; 

 as, for example, the different root crops possess a nutri- 

 tive value in proportion to. the amount of nitrogen they 

 contain, but the nutritive value of a root ought not 

 to be compared with a succulent plant, like clover, 



