3"24 Progress of Foreign Science. 



sweet principle, which are the result of saponification of dif- 

 ferent species of fats, is greater than the weight of the fat em- 

 ployed. If we recollect that the saponification takes place in 

 vacuo, without any other substance than the fat, the potash, and 

 the water, and that there is no disengagement of hydrogen and 

 oxygen, we must necessarily admit the fixation of water in one 

 of the products of the saponification. Comparative tables of 

 all the products and of their elements, whether in weight or in 

 volume, establish these consequences; and the author observes, 

 that, in the acidified fats, the hydrogen is to the carbon in the 

 ratio of the elements of olefiant gas. When we heat gently 

 with massicot (yellow oxide of lead) the margaric and oleic 

 acids, and consequently the acidified fats which are formed 

 from these acids, there is disengaged a quantity of water, which, 

 as the author shews, is formed of the combination of the hydro- 

 gen of these acids with the oxygen of the massicot, or which is 

 disengaged simply by the combination of the massicot with the 

 dry acids. The author adopts the latter opinion. He exhibits, 

 in comparative tables, the elements of natural fats, and the pro- 

 ducts of their saponification, both of the margaric and oleic 

 acid. There results from their comparison : 



1. That in the three margaric acids which he has examined, 

 the carbon is to the hydrogen perceptibly in the proportion of 

 the elements of olefiant gas. 



2. That the oxygen of the margaric acid of the sheep, is to 

 the oxygen of the margaric acids of man and the hog, nearly as 

 1 to 1^. From this observation the author proposes to name 

 the margaric acid of mutton suet, margarous acid. 



3. That in the oleic acids of man and the hog, there is more 

 oxygen than in the margaric acid ; and that in that of sheep 

 there is more than in margarous acid. 



It is remarkable that the composition of oleic acid is repre- 

 sented by olefiant gas -f oxide of carbon. 



When potash or any other alcaline base acts on the fats 

 which have been examined, the greater part of their carbon and 

 hydrogen, in a ratio very near to that of olefiant gas, retains a 

 portion of oxygen to constitute the margaric and oleic acids, 

 whilst the rest of the elements of the fat, that is to say, of the 

 carbon, hydrogen, and a quantity of oxygen, which seems less 

 by one-half than what would be necessary to burn the hydrogen, 

 form the sweet principle, by fixing probably a portion of water. 



The elementary analysis of cholesterine shews, by its excess 

 of carbon, the reason why this compound produces no margaric 

 acid, when it is exposed to the action of alcalies. 



At page 389, vol. x. of this Journal, we have given some ac- 

 count of the chemical researches of M. M . Pelletier and Ca- 

 ventou, on cinchonine and quinine. But the mode of obtaining 



