
FOODS, IN RELATION TO RESPIRATION AND FEEDING. 349 
much the larger proportion, is nearly doubled in the Fat one. ‘Thus, the 
increase in weight during the fattening process was found to contain as much 
as 72 per cent. of dry substance, of which only 0-436 is mineral matter, and 
only 1°33 nitrogen, equal to about 8} of proteine or gelatinous compounds. 
There is, however, about 632 per cent. of fat, or nearly eight times as much 
as of dry nitrogenous compounds. Indeed, it is seen in the table, that 88 
per cent., or about eight-ninths of the entire dry increase of this Fat Pig, was 
pure fat. 
M. Boussingault, in his ‘ Rural Economy,’ estimates that the Ox, the 
Sheep, and the Pig, contain from 33 to 4 per cent. of nitrogen; and more 
recently in his paper on the Formation of Fat in the Animal Body (Anz. de 
Chémie, vol. xiv. p. 444), he supposes 4 as the probable per-centage in the 
Pig. He also states (Rural Economy), that M. Payen estimates the increase 
of the fattening pig to contain about 16 per cent. of nitrogenous compounds, 
equal to about 25 per cent. of nitrogen. [t will be observed, however, that 
only about half of these amounts of nitrogen were found in the direct expe- 
riments of our own which we have quoted; and it should at the same time 
be remarked, that the Fat Pig in our experiment was by no means so fat as 
is usual, at least in this country. 
It is doubtless true, that other animals, as fed for the butcher, will generally 
contain more flesh and less fat than the pig. In a very fat sheep, however, 
fed for Christmas, and which was indeed too fat, we found a larger per- 
centage of fat, and as little nitrogenous substance, as in the moderately fat 
pig, whose composition has been given above. Among our experiments on 
this subject, it was only in the case of a lean ox, that we found the nitrogen 
to exceed 24 per cent. of the entire animal; whilst in all the cases of store 
or lean animals, the per-centage of dry fat was much greater than that of the 
dry nitrogenous compounds. 
The fact that fat is in so mucha larger proportion than lean in the animals 
fed for the butcher, would seem not only to be consistent with the results of 
our experiments as to the great influence of the non-nitrogenous constituents 
of the food of these animals in the production of increase during the fattening 
process—but it indicates also the predominance of this non-nitrogenous cha- 
racter in that description of human food (buteher’s meat), which is generally 
spoken of as the most nitrogenous, and therefore the most nutritive. 
That the fatty matter of the food is not the only source of the fat stored 
up in the body of the fattening animal, is illustrated by a further consi- 
deration of the circumstances and results of this same experiment with pigs. 
Thus, in the following table are shown the amounts of Gross Dry Sub- 
stance—of Mineral Matter—of Dry Organic Matter—of Total Non-nitro- 
genous constituents—of Nitrogenous constituents—and of fatty matter, stored 
up in the Fat Pig, for 100 lbs. of each of them consumed as food. 
Table IX. 
Showing the proportion of certain constituents stored up in the Fattening Pig 
for 100 of each of them consumed as food. 

: ;Consumed | Stored up | Expired, 
Constituents. as in the | Perspired, 
Food, Animal, |or Voided. 








Gross dry substance ......... | 100 | 15:04 84:96 
Mineral matter ............... ; 100 | 219 | 97°81 
Total dry organic matter...... 100 15°59 84-41 
Non-nitrogenous constituents) 100 17-74 82-26 
Nitrogenous constituents +» 100 8°35 91-65 

Fatty matter ......., ssoaent «| 100 407-00 

