678 AZOTISED AND NON-AZOTISED FOOD. 
little value, except as data for the deduction of principles;” how¬ 
ever, we proceed to examine the inference at length, “that non- 
azotised food produces serum.” 
We first take the composition of non-azotised compounds as a 
class, and we find them chemically constituted of carbon and hy¬ 
drogen, with a small proportion of oxygen, but devoid, as their 
name implies, of nitrogen or azote: in the second place, taking the 
constitution of serum, we discover in 1000 parts there exists 900 of 
water, and of the remaining hundred 86 parts of albumen, a highly 
azotised principle, the salts of soda and potass making up the total. 
Now, then, comes the question, can serum be formed from matters 
which bear no relation to it in chemical constitution 1 No species of 
reasoning can convince us that albumen can be formed from non- 
azotised food—can it, then, from the water 1 Truly, we have the 
elements requisite to form watery vapour, but be it remembered 
that 1700 cubic feet of watery vapour will be condensed to one 
cubic foot of water, and then what becomes of the carbon and ex¬ 
cess of hydrogen? Further, it would be very inconsistent with 
a knowledge of Nature’s economy to accuse her of having recourse 
to such a complication of proceeding for the attainment of so simple 
an end. But there is no necessity to have any supposition in the 
argument. I think I have demonstrated the position to be a che¬ 
mical impossibility, inasmuch as the only organic principle in serum 
is albumen, which is not present in non-azotised food, while the 
main bulk is water, which is taken into the system ready formed. 
Let us now proceed to the second original inference, which is 
comprehended in this sentence, “ May we not physically infer,” he 
says, “ that fat is a secretion from the serum of the blood, and its 
formation the result of atomic arrangement in the cells of the adi¬ 
pose tissue.” This inference he bases on the fact, that serum is 
in excess in fat animals, stating his opinion in the concluding part 
of his paper, that the “ non-azotised matters go to the production 
of serum, and thus contribute to the formation of fat.” Now, it 
appears to me that had Mr. Read generalized his ideas a little he 
would never have fallen into such an extraordinary error; for while 
he would undoubtedly have observed an excess of serum in fat 
animals, he would have discovered the same phenomenon in lean 
ones, even to a more marked degree. 
However, entertaining the proposition for the sake of argument, 
we must proceed to ascertain the relation serum bears to fat in 
chemical constitution; the point, however, is so connected with my 
prior arguments that it will require but little consideration. Serum 
we have ascertained to consist of albumen, water, and a few salts; 
fat we know to comprise carbon, hydrogen, and a small proportion 
of oxygen ; in fact, analogous in composition to non-azotised food : 
