AROMATIC ACIDS OF FLESH. 115 



that it contains 72 carbon-atoms, what is the number and what 

 the complexity of the aplone molecules between which these 

 7 2 carbon atoms are divided ? All we can say is that no aplone 

 molecule with more than 7 or 8 carbon atoms has hitherto been 

 produced by its natural or artificial decomposition, so that its 

 constituent residues probably appertain to much simpler mole- 

 cules, than do the residues of ordinary fat. 



(123.) The other point of interest connected with the artificial 

 oxidation of flesh is, that the acids and aldehydes thereby 

 produced belong to both our primary series, namely, the fatty 

 and the aromatic ; so that while the oxidation of muscle in the 

 laboratory yields us certain fatty acids which are producible by the 

 similar oxidation of fat, it yields in addition certain acids of the 

 aromatic series that are not producible by the oxidation of fat. 

 This result acquires additional importance from the consideration 

 that chemists are at present quite unable to transform fatty into 

 aromatic compounds, or vice versa, by any definite reaction. It 

 is true that when various bodies of the fatty class are subjected 

 to a full red heat, some products belonging to the aromatic class 

 are formed; but this transformation is one that we cannot 

 trace. It belongs to the class of changes which are termed 

 destructive or indefinite, in contra-distinction to those easily 

 traceable and definite reactions which we call more especially 

 metamorphic. By no ordinary treatment with reagents, and cer- 

 tainly by none of the modes of treatment to which muscle has 

 been subjected, are we able to pass from the fatty to the aromatic 

 class of bodies ; and accordingly, when we find, by treating 

 flesh, &c., with sulphuric acid and manganese, that both aro- 

 matic and fatty acids are produced, we have a right to infer that, 

 be the exact composition of the flesh what it may , it certainly 

 contains, in addition to its ammonia residues, one or more resi- 

 dues of compounds belonging to the fatty, and one or more 

 residues of compounds belonging to the aromatic class. This 

 conclusion becomes even more irresistible when we consider 

 that not only by the direct oxidation of nitrogenous tissue now 

 taking place on the table, but by its indirect oxidation, through 



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