FOOD AND FEEDING. 387 



consume, seems very well calculated to assist the practical farmer 

 in managinor the food of the animals upon his land ; for if flesh, fat, 

 and bone exist all but ready formed in the food, it is obvious that 

 the best kind will be that precisely which, under the same weight, 

 contains the largest quantity of the various matters of the organi- 

 zation. 



It is by no means easy to ascertain precisely the amount of the 

 azotized constituents, gluten, and albumen, contained in plants ; to 

 do so requires both time and pains. But let it be once admitted that 

 the nutritive properties of forage increase in the precise ratio of 

 these matters, this is clearly as much as to say that the value is in 

 proportion to the quantity of azote contained in the food, and that it 

 becomes a matter of the highest moment to have at hand a ready 

 mode of determining the point. I believe it infinitely better to get 

 at the quantity of azote immediately, which is easily done, than by 

 any roundabout and laborious process to ascertain the amount of 

 albumen and gluten : the quantity of azote ascertained, it is most 

 easy to deduce the quantity of albumen and gluten — in other words, 

 o^ flesh — contained in each particular species of food examined ; for, 

 as a general rule, vegetable food does not contain any other azotized 

 principle. It is true, indeed, that all the azotized principles of vege- 

 table origin cannot be considered as nutritious ; some of them, on 

 the contrary, are virulent poisons or active medicines, according to 

 the dose in which they are administered. But these poisonous sub- 

 stances are not met with in appreciable quantity in the plants which 

 are commonly grown for the food either of man or beast. Still, all 

 the truly nutritious articles of food contain an azotized principle. 

 The experiments of M. Magendie have shown, that substances which 

 contain no azote, such as sugar, starch, oil, will not support life ; 

 and, on the other hand, it is ascertained that the quality of alimentary 

 matter, flour for example, increases with the amount of gluten which 

 it contains. It is because the seeds of the leguminous vegetables 

 are richer in azotized principles — that is, in flesh — that they are also 

 more highly nutritious than the seeds of the cereals. 



These several considerations, therefore, induce me to conclude; 

 that the nutritious principles of plants and their products reside in 

 their azotized principles^ and consequently that their nutritious pow- 

 ers are in proportion to the quantity of azote they contain. From 

 what precedes, however, it is obvious that I am far from regarding 

 azotized principles alone as sufficient for the nutrition of animals ; 

 but it is a fact, that every highly azotized vegetable nutritive sub- 

 stance is generally accompanied by the other organic and inorganic 

 substances which concur in nutrition. 



In seeking to learn the precise quantity of azote contained in a 

 great number of articles used as food for cattle, I have had it in 

 view particularly to find a standard or fixed point for estimating their 

 comparative nutritive properties. It is long since more than one of 

 the most distinguished farmers, both of England and Germany, 

 essayed to resolve this important problem in rural economy. Thua 

 Thaer and many others have given tables of the quantities by weight 



