OXIDE OF LIPYL. 239 



OXIDE OF LIPYL. C 3 H 2 O. 



On boiling one of the common fats or fatty oils with a caustic 

 alkali, with the hydrate of an alkaline earth, with hydrate of mag- 

 nesia, or oxide of zinc or of lead, the fat, without assimilating 

 oxygen, or giving off hydrogen, is decomposed into one or more 

 fatty acids, which combine with the base that has been employed, 

 and form soaps, and a peculiar sweet matter, glycerine. On com- 

 paring the weight of the resulting products of decomposition with 

 that of the fat which was employed, we find that an increase of 

 weight has taken place in consequence of an assimilation of water. 



In order to explain the nature of this process, it was assumed 

 that the fats are combinations similar to the salts of oxide of ethyl, 

 and that glycerine, represented by the formula C 3 H 2 O, constituted 

 the base of the fats ; but the constitution of glycero-sulphuric acid 

 proves that glycerine must be represented by the formula C 6 H 7 O 5 , 

 and that consequently it cannot be regarded as the base of the 

 neutral fats. Hence it is probable that the fats contain, in addi- 

 tion to the fatty acid, the oxide of a radical, having the composition 

 which was formerly ascribed to glycerine ; and that this oxide in 

 its separation from the fatty acid assimilates water, and is con- 

 verted into another body, as in the case of oxide of ethyl when it 

 is expelled by an acid from its combination. To this hypothetical 

 radical, Berzelius has applied the name of lipyL 



That the base in the fats is not glycerine seems obvious also 

 from the circumstance that hitherto no neutral fat has been pre- 

 pared from glycerine and the fatty acids. Whether the butyrin 

 that has been artificially formed from glycerine and butyric acid 

 has the same composition with that contained in butter has not yet 

 been ascertained. Acrolein, which is polymeric with oxide of 

 lipyl, and is a product of distillation of glycerine, cannot, any more 

 than glycerine, be the base of the fats, since it cannot be made ta 

 combine even with strong acids. 



This conversion of the fats into acids and glycerine, may be in- 

 duced by other bases than those we have already mentioned, namely, 

 by the soluble carbonates and borates, if they be digested with the 

 fats for a sufficiently long period. 



In the case of the carbonates we must, however, suppose that 

 in this process the alkaline carbonate is first resolved into alkaline 

 bicarbonate and free alkali, and that it is the latter only which takes 

 part in the saponification ; and that, on further boiling, the alkaline 



