FATS. 269 



tion representing the formation and function of certain cells can be 

 established, fat will constitute one of the integral factors. Indeed it 

 is impossible to believe that in the vital activity of cellular action, fat 

 should be without influence on the metamorphosis of the substances 

 which it accompanies, and that without reference to them, it should 

 obey only its own affinities towards oxygen or an alkali. 



In considering fat as an important agent in the various phases 

 of the metamorphosis of animal matter, we cannot, however, refer 

 its action solely to mere contact or a catalytic force, but we are 

 constrained to assume that it cooperates in the metamorphic action, 

 and experiences metamorphoses, combinations, and decompositions. 

 None but those chemists, who, imagining they comprehend Liebig^s 

 views, have framed and illustrated a physiology of their own, in the 

 same manner as speculative natural philosophers have attempted 

 a priori to construct the laws of the natural sciences, could have 

 regarded the animal body as a furnace, and fat as a simple and crude 

 material of combustion. It is, however, the province of physiological 

 chemistry to trace the chemical phenomena of the animal body and 

 its various substances in their separate phases of metamorphosis, and 

 from the knowledge thus obtained, to sketch the grand and univer- 

 sal features of chemical action in the living body. It would be 

 equally unphysiological and unscientific to suppose that the require- 

 ments of physiology would be fully satisfied by our proving that fat 

 becomes finally decomposed into carbonic acid and water. The 

 province of physiological chemistry is rather to show whether fat, 

 or rather the fatty acids, always gradually and successively lose two 

 atoms of carbo-hydrogen, that is to say, whether remaining in accor- 

 dance with the general formula, they become converted into acids of 

 the first group, and are then finally decomposed into carbonic acid 

 water ; or whether fats contribute by their metamorphosis in the 

 animal body to form other known animal substances. As, how- 

 ever, in the present state of our positive knowledge, we are unfor- 

 tunately not in a position to answer this question with certainty, it 

 is better to confess our ignorance, than to indulge in vague conjec- 

 ture, although many chemical and physiological experiments afford 

 some support to the hypothesis, that the fats take a part in the 

 formation of other substances which cannot be regarded as mere 

 products of their oxidation. 



Since we find so large a quantity of saponified fats in the blood 

 and other animal fluids, as for instance in the bile, it is not impro- 

 bable that the first step in the alteration of the fats consists in their 

 decomposition into glycerine and the corresponding fatty acids. 



