548 ]vni. J. B. LAWES AIsD EE. J. H. GILBEET OX THE COHPOSITIOX OE 
It will be remembered, that in the average of the cases in which the Sheep had been 
fed upon a liberal mixed diet of dry food and succulent roots-atoittedly 
conditions for their increase-they gave orrly about 9 per cent of dry mcrease, for 100 
dry substance of food. The average of the 24 lots of Pigs (80 animals) shojs on the 
other hand, nearly double as much, or IT'27 parts of dry mcrease, or o y oo 
consumed. The yield of fat, and of nitrogenous compounds, of which these 1 . . pans 
are chiefly made up, is of course higher in a con'esponding degree. en it is ome 
in mind, however, that the natural fattening food of the Pig consists chiefly of npene 
seeds containing little indigestible woody flbre, or immatoed vegetable products and 
that that of the Sheep contains a large proportion of woody flbre, and also muc o c 
less highly elaborated vegetable compounds, it wiU not appear siu-prising, that 100 paits 
of the dry substance of the food of the Pig should yield so much more of diy anima, 
increase, than 100 parts of that of the Sheep. It residts, of course that of the fatte^ 
food of the Pig, a less proportion of the dry substance than of that of Sheep, wi e 
eM, persinred, or voided. In the case of the Sheep, it was assumed, as the avemge 
of the cases wherein the food was of the most favomable kind, that about 91 pel cent, 
of the chy substance consumed were in some form expired, perspued, or voided In the 
case of the single analysed Pig, only 85 parts were expired, perspired, or voided, tor 100 
of diy matter consumed in food. And, taking the average of the twenty -foui lots com- 
prising the eighty animals, calculation shows only 82-7 parts of collectii e diy su stance 
expired, perspired, or voided, for 100 consumed in the food. 
In speaking of the proportion of dry substance stored up in increase, lor a gixei. 
amount consumed in food, it will not for a moment be assumed, that it is herem imphed 
that the relation of the ultimate elements is the same in the diy matter assimilated and 
fixed, and in that given off in the various forms from the system. The leiy laiioiis 
amounts, respectively of mineral matter, of nitrogenous compounds, and 
genous substance (fat), stored up for 100 of each consumed (as shonm in Tables Ml. 
and XIII.), give some means of judging how different must be the ultimate composinoii 
of the gross diy matter fixed in the body, from that of the matters of the food ehiin- 
nated from it. It is not within the scope and object of the present Paper, to giie aiiy 
further indication of the composition of the matters collectively given off from the body 
ill relation to those taken as food, than is implied in the figures in the Ta es jusl 
referred to, which show the amounts of certain constituents stored up foi a given amount 
consuined-the complementary quantity being of course that which is expired persjivd. 
or voided. Still less is it to our present purpose, to show the proportion ot the i eieii 
constituents of the matters collectively given out from the body, which wdl be respect- 
ively exhaled by the lungs, perspired by the skin, or voided iii the iqui oi le so u 
form. There is, however, one point in connection with the difference betiieen le is t 
mate composition of the dry substance of increase, and that of the compounds ot t ho 
food which produced it, which may be here appropriately illustrated ; t us is, “ ‘‘y ‘ 
tion of the fat in the mcrease, to the /(it and other matters m the food, which y le i e i . 
