478 
On the Composition of Oxen, Sheep, and Pigs, 
In the case of both the oxen and the sheep, there is a striking' 
uniformity in the proportion of the mineral to the nitrogenous 
matters of growth. In the pig, not only is the actual amount of 
mineral matter much less, but its proportion to the nitrogenous 
matters seems to decrease as the animals fatten. Thus, the pro- 
portion of mineral matter to 1 of nitrogenous substance was, in 
the carcass of the lean ox, 0"31, of the fat ox 0"30, of the store- 
sheep 0"30, of the fat sheep 0'30, and of the very fat sheep 0'30. 
On the other hand, in the carcass of the store-pig, the propor- 
tion of mineral matter to 1 of nitrogenous substance was 0"183, 
and in that of the fat pig only 0-133. It would appear, there- 
fore, that the amount of mineral matter in the increase of the 
faj;tening pig will be less than in that of the sheep, both in pro- 
portion to the total increase itself, and to the coincidently accu- 
mulated nitrogenous compounds. 
When it is remembered that the usual fattening food of the 
pig consists largely of ripened seeds, containing comparatively 
little indigestible woody fibre, or immatured vegetable products, 
it will not appear surprising that 100 parts of the dry substance 
of its food should yield much more dry animal increase than 
100 parts of that of the sheep. In the case of the sheep it was 
assumed (as the average of the cases wherein the food was of the 
most favourable kinds), that for 100 parts of dry substance con- 
sumed, only about 9 parts of dry increase were produced, and 
that 91 parts were in some form expired, perspired, or voided. 
Calculated in the same way, there were, in the case of the ana- 
lysed fat pig, only 85 per cent, of the dry substance of the food 
expired, perspired, or voided. And, taking the average of the 
24 lots of pigs, comprising 80 animals, similar calculations 
show only 82"7 per cent, of the dry substance of the food ex- 
pired, perspired, or voided. 
The relation of the ultimate elements in the total dry matter as- 
similated is, of course, very different from that in the total matters 
given off in the various ways from the system. It is not within 
the scope and object of the present paper to consider the com- 
position of the matters collectively given out from the body, and 
still less to determine the proportions, respectively, expired by 
the lungs, perspired by the skin, or voided in the liquid and 
solid excrements. Some illustration of the difference in ultimate 
composition, between the dry substance of the food, and that of 
the increase produced from it, will be brought to light in what 
now follows. 
3. Relation of the Fat stored up in the Increase, to the ready-formed 
Fat, and other constituents, consumed in the food, S^'c. 
In the majority of the experiments with the pigs, the amount 
of ready-formed fatty matter in the fond was determined. Com- 
