1818.] their Combinations with Alkalies-. 269 



fication is much more difficult than the determination of the same 

 point with respect to the stearines. The stearines are less sub- 

 ject to be changed than the elaines ; it is less difficult to obtain 

 the stearines in a uniformly pure state ; besides the saponified fats 

 of the stearines being less fusible than the saponified elaines, it is 

 more easy to weigh them without loss. The elaines of the sheep, 

 the hog, the jaguar, and the goose, extracted by alcohol, yield 

 by the action of potash, 



Of saponified fat 89 parts 



Of soluble matter 11 



The elaine of the ox extracted in the same manner yields 



Of saponified fat 92*6 parts 



Of soluble matter 7-4 



The memoir terminates with the following general conclusions. 

 The different kinds of fat, considered in their natural state, are 

 distinguished from each other by their colour, odour, and 

 fluidity. 



The cause of their colour is evidently a principle extraneous to 

 them, since they may be obtained colourless. It is the same 

 with respect to their odour ; for if we do not always deprive 

 them entirely of it, we can remove a portion of it, which is suffi- 

 cient to prove that it must not be confounded with the fixed fatty 

 bodies from which it has been separated. The reduction of the 

 different kinds of fat into stearine and elaine explains the differ- 

 ent degrees of fluidity which they possess ; but it may be asked, 

 whether we ought to regard stearine and elaine as composing 

 two genera, which embrace various species, or as two species, 

 each of which may be absolutely represented by a stearine or an 

 elaine obtained from any one of the fats which have been 

 described above. 



If the stearines and elaines are identical, they ought to exhibit 

 exactly the same phenomena, when they are placed in the same 

 circumstances, under all possible relations. They should have 

 the same external appearance, the same solubility in alcohol, the 

 same decomposition by potash, and consequently the margaric 

 and the oleic acids, and the sweet principle which they yield, 

 bhould be identical, and in the same proportion. Viewing the 

 subject in this manner, we may easily answer the question, for 

 we have only to examine whether the stearines and the elaines 

 actually present this identity of properties. Now we have 

 observed differences between the stearines when they have been 

 brought to the same degree of fusibility. Those of the human 

 subject, of the sheep, the ox, and the goose, coagulate into a 

 mass, the surface of which is flat ; that of the hog into a mass, 

 the surface of which is unequal. The stearines of the sheep, the 

 ox, and the hog, have the same degree of solubility in alcohol ; 

 the stearine of man is a little more soluble, while that of the 



