ANALYSIS OP BUTTEE-PAT. 73 



to believe that a similar acid might yield hutyrate instead of 

 acetate, under similar circumstances. 



Mr. Wanklyn attributed the presence of butyric acid in 

 the soap to the occurrence of such acids ia the fat. As the 

 difficulty of aJialysis of such substances as fat, and the 

 separation of the fatty acids is exceedingly great, if not in- 

 surmountable, it is by no means easy to disprove or prove 

 this theory (which of course does not reflect upon the practical 

 applicability of our method). But the facts seem strongly to 

 speak against its correctness. One would suppose, if such 

 splitting up took place, it would do so by degrees, more ia 

 a hot solution than in a cold one, more with excess of 

 alkali than with a small quantity. Yet the amount of , fatty 

 acids obtained is the same, whether the saponification take 

 place in a boUing alcoholic solution or with aqueous alkali, 

 or in the cold, as an interesting experiment by Dr. Dupr6 

 shows, who saponified in cold alcoholic solution, decomposed, 

 and washed with large quantities of cold water. Against the 

 theory further speaks the great specific gravity of butter-fat, 

 as treated of at length in another chapter. 



The decomposition of such acids, moreover, only takes 

 place when fused caustic alkalies act upon the fatty acids, 

 hydrogen being evolved ; and there beiag, in the case 

 of butter-fat, no great excess of alkali, we must entirely 

 reject Mr. Wanklyn's otherwise ingenious theory. 



At the same time it must be admitted that butyric acid does 

 not exist in butter-fat as butyrate of glycerine. Mr. Bell 

 has pointed out that if butter consisted simply of a mixture 

 of glycerides, it could not be difficult to extract, by means of 

 alcohol, the easily soluble butyrate, leaving the palmitate, 

 stearate, and oleate for the most part undissolved. But, as 

 the following quotation from Mr. Bell's paper wiU show, it 

 appears that butter-fat contains the butyric acid intimately 

 combined with the other fatty acids. 



