ON SOME OF THE ANIMALS FED AND SLAUGHTEEED AS HUMAN FOOD. 541 
It will be observed, by reference to the columns in Tables IX. and X. respectively, which 
show the proportion of the total non-nitrocjenous to the total nitrogenous constituents 
of the food, that it was in some cases nearly double as much as in others. It might be 
m-ged, therefore, that it was quite irrelevant to apply one and the same composition to 
the final weights of animals fattened on foods dififering so widely in this respect. It is 
not denied, that, other things being equal, a highly nitrogenous food may give some 
tendency to a greater proportion of increase in frame and flesh ; but all observation would 
lead to the conclusion, that, at least with animals fattening under ordinary conditions, 
this would happen but in a very limited degree ; in fact, by no means in anything like 
a numerical proportion to the increased relation of the nitrogenous to the non-nitroge- 
nous constituents of the food. It has been found, indeed, that as our current fattening 
food-stufifs go, the increase in weight is more in proportion to the amount of digestible 
non-nitrocjenous, or total dry organic substance^ than to that of the nitrogenous com- 
pounds consumed. And, although with a high proportion of available wow-nitrogenous 
matter in the food there is a somewhat less tendency to increase in frame, and a greater 
one to fatten, yet animals which have been fed on very highly nitrogenous food, though 
as a rule they have appeared to grow somewhat more, have nevertheless frequently been 
extremely fat. Upon the whole then it is concluded, that the relation of the nitroge- 
nous matter to the fat, in the increase of the fattening animal, is by no means increased 
in the degree which might be expected, by a considerable increase in the proportion of 
the nitrogenous to the non-nitrogenous compounds in the food. The proportion of the 
nitrogenous matters in the increase is, there is little doubt, much more aflected by the 
age and habits of the animal than by the proportion (if not below a certain limit) of 
the nitrogenous constituents in the food. From these considerations, and owing to the 
comparatively small proportion of the several constituents of the food actually stored 
up and retained in the increase, any error arising from adopting the same composition 
for the final weights of animals fattened on very various foods, u 111 be immaterial in 
forming general and average estimates of the proportion of the constituents stored up in 
the increase, to those consumed in the food. With these explanations ’ hen, and calling 
attention to the reservations which they obviously imply, we adopt as they stand, for the 
basis of our calculations, the records of constituents actually consumed, and the estimates 
of the composition of the increase produced as given in Tables IX. and X. respectively, 
and proceed at once to consider the indications so obtained. 
From Table XII. it is seen, that taking the average of the numerous experiments with 
Sheep, rather more than 3 per cent, of the total mineral moMer consumed in the fatten- 
ing food would appear to be retained in the increase. Assuming the due correction made 
foi the extraneous mineral matter in the wool of the fat animals analysed, the average 
of the cases in question would show rather less than 3 per cent, of the mineral matter 
consumed, to be stored up in the increase. In Class IV. dry food alone was given, and 
such as contained a large proportion of mineral matter to digestible organic substance. In 
this case, therefore, the 'proportion of the consumed mineral matter which appears to be 
MDCCCLIX. 4 3 
