672 ME. J. B. LAWES AND DE. J. H, GILBEET ON THE COMPOSITION OP 
Before any legitimate comparison can be drawn between the composition of our Animal- 
fooTand t Jt of Bread, in regard to the proportion in each, of the Aon-mtrogenons or 
yo^-flesh-forming, to the Sitrogemue (or so-caUed “ Blesh-fornimg") constituents, it .s, of 
course necessary to form an estimate of the probable relative values, for the pm-poses of the 
rtem of a given amount of the Fat in the one, and of the Starch which predom^tes 
n tr ther. In calculating the amount of Starch which would be required to produce a 
It amount of the m»d Fats of the animal body, it was decided on grounds that were 
ftated (p. 551), that 2-5 parts o{ Starch might be assumed to.be reqmsite for the formation 
of ipt of L It was stated, that assuming the ^.edfats of the fattening a^a 
to coLin, in round numbers, 77 per cent, of caibon, 12 per cent, of hyiogen, a 
per cent of oxygen, it would take pretty exactly 2-46 parts of pure Starch to supply he 
Tecessly carbo! a^d hydrogen for 1 part of such a raided and to yield, at the 
“me time, oxidable malerial (carbon and hydrogen), to carry off the whole of the super- 
Zus oxygen of the Starch, as carbonic acid and water. But, this bemg the nun, mum 
Lount of Starch required, and owing also to other considerations stated, the — en. 
number 2 -5 was taken as the amount of Starch requiied to produce 1 part of the ^ 
Fats ill the fattening animals. The «n-nitrogenons substance (not fat) luBiead con- 
sists chiefly of SWi^part of it in a more or less altered condition. There is also 
a small but variable amount of indigestible matter, and of compounds haimg a some- 
what lower percentage of carbon than Starch itself. We may safely take, then, for our 
isenrpurpose, the number 2-5 as representhig the amount of the ,n^ed Starch and_ 
the otlJ nm-nitrogenms mbstances in Bread (excluding fat), which w^ 
o 1 plrt of Fat, ior the purposes of storing up Fat in the human body. B would, o 
ourse L quito out of place in such a calculation, to take into account any shg 
differeiice between the composition of the mixed Fats in the human body, and ot tho.e 
nf the slaughtered animals used as its food. i , 
In the converse estimate to the above, namely, that of how ^ 
be equivalent to 1 part of the mixed Fats in oxygen-satiuating capacity that i., ^ - 
;:ii7o:es of res,u-Lu-.e get of course the same figure 2-45. Biff for ‘ 1 - equiim™ 
of the mixed Starch and other non-iiitrogenous constituents exc " “8 “ ’ *■ 
number 2-5. In this purely chemical point of view, therefore, we take 1 pmt ot > ^ 
in Animal-food, as equal, in respiratory and fat-forming capacity, to paits 
“ato’unt!r5 ill the Carcasses-or in the estimated total consumed portions of 
the ttL animah-has then only to be multiplied by 2-5 to bring it to its starAc 
equivalent ; or rather, to its equivalent of the mired sta,rh and rtc ortcr 
matters in Bread. This “starch-equivalent” of the Fat diiided 5 . ‘ 
nitrogenous constituents, gives, of comse, the relation ot the more *P“'f > > 
and Fat-forming constituents to 1 of Nitingeiioiis matters, 111 the ammal substance,. ■ 
such a form that these can be compared, in this respect, with rea . 
From all the information at command, we take the average composition of good 
