552 ME. J. B. LAWES AND DE. J. H. GILBEET ON THE COMPOSITION OF 
the source of the Fat, a rather larger quantity than of Starch would be requn-ed. Ot 
the pecUne bodies, again, which enter so largely into the roots which frequently constitute 
a large proportion of the fattening food of sheep and oxen, the quantity requu-ed would. 
on the same mode of calculation, be still more than of Sugar. 
On a former occasion, it was shown, that according to the mode of estimation here 
supposed, the 15 parts of dry solid increase yielded during the fattenmg process by the 
analysed fat Pig for 100 parts of dry matter of food consumed, would have required 
for its formation about 30 parts of the dry substance of the food consumed. The actual 
tiffures relating to this single animal are given in Table XVI., at the head of the respective 
columns which refer to the numerous lots of Pigs, the Fat in whose food was determmed 
by analysis, and that in their increase estimated. ^ . -d- 
For 100 dry matter in food, the dry matter in the increase of the analysed fat Pig uas 
14-94, and that taking the average of all the other cases in which the Fat m the food 
was determined was 17-40. Of these amounts of total dry substance assimilated, I-d-- 
xn the case of the single fat Pig, and 16-04 in the average of the other lots, are esti- 
mated as Fat. . , o OP ^ { 
Of the 13-2 parts of Fat stored up in the increase of the smgle ammal, 3-^6 oiili (pro- 
vided the whole supplied had been taken up) could have been derived from the Fat m 
the food. At least 9-94 parts must, therefore, have been formed in the body o. tie 
animal from some other constituent or constituents. If the constituent in quebtion 
were primarily Starch, it would, on our basis of calculation, require 24-8 paris o > 
Starch for the formation of the 9-94 parts of ^produced Fat. Of ready-formed Fat m t c 
food, and Starch, thus contributing to the formation of Fat, taken together, there uom 
therefore be 28-11 parts out of 100 of dry matter of food consumed, dn-ectly enpged 
in the storing up in the body, of the 13-2 parts of Fat. If we add to this, the T - 3 part 
of nitrogenous and mineral matters at the same time fixed in the increase, we hmc 
29-84 parts out of the 100 of dry matter of food consumed, directly contributing, m the 
sense supposed, to the production of the 14-94 parts only, of dry increase. In t le 
particular sense here implied, therefore, there would be only 70-16 parts of t le ^ o 
dry matter of the food expired, perspired, or voided, mthout thus directly contn muig 
to increase; instead of 85-06 parts, which is the ditference between the 100 ot dri 
matter in food, and the 14-94 only, of dry substance actually stored up. 
Following the same line of illustration for the average result of all the other experi- 
ments cited, it appears that for 16-04 parts of Fat stored up in increase, for 100 ot di> 
matter of food consumed, only 3-96 parts could have been derived riom ready-formed 
fatty matter supplied in the food. At least 12-08 p-arts must, therefore, Iniie been 
formed from other substances. If from Starch, it would require, at the rate ot ^ h pai ^ 
Starch for 1 of Fat, 30-2 parts of that substance for the formation of the 12 8 parts ot 
the produced fat. The ready-formed Fat, and the Starch, together thus contributing to 
the 16-04 parts of Fat in the increase, would amount to 34-16 parts of the 1 o 
food consumed. There were, further, 1-36 part of nitrogenous and mineral matteis 
