36 



mainly of three distinct compounds united in very various proportions. 

 One of these compounds, oleine, is liquid at ordinary temperatures, 

 the other two, margarine and stearine, are solid ; and, according as 

 the liquid or solid constituents preponderate, the body assumes the 

 consistence of oil, or of a fat less or more hard. He also showed 

 that each of these three principles contains a distinct fatty acid 

 united with the basis of glycerine, the sweet principle of oils ; that, 

 when the fat or oil is acted on by alkalies or other metallic oxides, 

 the basis of the glycerine is displaced, combining with water at the 

 moment of its separation, thus forming true glycerine. The fatty or 

 oily acid in the meantime unites with the alkali or metallic oxide : 

 when the alkalies are used to effect the saponification, soluble soaps 

 are found ; when metallic ox4des, such as oxide of zinc, or oxide of 

 lead, are employed as the saponifying agents, a plaster, or insoluble 

 metallic soap, is formed. 



But the discoveries of M. Chevreul were of far higher value in 

 a scientific point of view than the mere establishment of facts, or 

 the discovery of new bodies of importance in the arts. The methods 

 of research which he introduced, laid the foundation of future 

 inquiries, and may be said to have enabled Organic Chemistry to 

 become what it now is. 



At the time when the researches of M. Chevreul were commenced, 

 no trustworthy process of ultimate organic analysis existed. A 

 method capable of furnishing results, which, for accuracy, though 

 not for rapidity and facility of execution, challenges comparison with 

 those at present in use, was by him devised and applied. But a 

 still more important aid to these inquiries was supplied. M. Che- 

 vreul was the first to perceive that the numerical results obtained by 

 ultimate analysis of an organic compound were not the only data 

 necessary to fix its true composition, and he first pointed out the 

 importance of an extended study of the changes produced in each 

 compound by the action of reagents. 



The merit of recognizing and systematically introducing this 

 leading principle into the methods of research practised in Organic 

 Chemistry is due to M. Chevreul ; and the important services which 

 he has thus rendered to the progress of Organic Chemistry are felt 

 more and more in each succeeding year. Like other great men, 

 M. Chevreul was in advance of his age, and a few years elapsed 



