DESTINATION OF NON-AZOTIZED ALIMENTS. 151 
155. Now, in regard to the non-azotized, or the saccharine 
and oleaginous groups of alimentary substances, it appears to 
be an established fact, that none of the higher animals can be 
permanently supported upon them alone. Thus, dogs that 
have been fed on sugar and starch only, do not survive long ; 
and it is evident, before their death, that their tissues are 
ually undergoing decay. It has been thought that such 
results might be partly explained upon the fact, that animals 
fed upon one simple substance soon become disgusted with it, 
and will even refuse it altogether ; but the experiments have 
been repeated with a combination of various non-azotized sub- 
stances, and the same result has occurred. Still it is too much 
to affirm, as some have done, that these substances do not con- 
tribute in any degree to the nutrition of the animal tissues; 
since there is ample evidence that the presence of fatty matter in 
the blood is a condition essential to the production of newly 
forming tissue ; and we find that either oleaginous substances, 
or substances belonging to the saccharine group which can be 
readily converted into fat within the body, constitute an im- 
portant part of the food of Man, and of animals generally.* 
156. That such a conversion can take place, has been de- 
monstrated by experiments carefully conducted upon bees, 
which have been found to generate wax when fed upon sugar 
only ; and also upon cows, which give off in their milk so 
much larger a quantity of butter than can be produced at the 
expense of the fat contained in their food, that there is no 
other mode of accounting for its presence, than by regarding 
it as generated from the starchy portion of their diet. And 
the fattening power of starehy and saccharine articles of diet 
is well known to breeders of cattle ; though the articles which 
contain oily matter in addition seem to possess a higher value 
in this respect. 
157. But if these non-azotized compounds, which exist so 
_ largely in the food of herbivorous animals, are not destined 
to form any other permanent part of the animal organism 
than the oleaginous contents of the fat-cells (§ 46), the ques- 
tion again arises,—what becomes of them? It is not enough 
1 The value of cod-liver oil, which is now so extensively used in the 
_ treatment of diseases of imperfect nutrition, seems to depend upon the 
'_Yeadiness with which it can be digested and assimilated, so as to furnish 
the supply of fat required by the formative processes. 
