562 M. Chevreul on Fatty Bodies, and [Oct. 



The saline residuum obtained from the soap of mutton fat 

 weighed -06 gr. ; but it seemed to contain a small portion of the 

 sweet principle. By adding phosphoric acid, a rank odour was 

 disengaged, mixed with thai of acetic acid. The saline resi- 

 duum of the soap from the fat of the ox was in too small a 

 quantity to be appreciated, yet the aqueous fluid proceeding 

 from the decomposition of the soap was acid and amber coloured ; 

 the odour was precisely the same with that which is disengaged 

 from oxen, when they have been heated by exercise. The odor- 

 ous principle is more developed in the fat of the jaguar by being 

 saponified ; the odour is not easily defined, but is thought to 

 resemble that which is sometimes perceived in the menageries of 

 wild beasts. From these observations we may conclude, that 

 the action of potash develops in the fat of the sheep, the ox, 

 and even of the jaguar, odorous principles, which are analogous 

 to, if not absolutely identical with, those which the animals 

 exhale under certain circumstances, and that an acid property 

 accompanies' these principles. 



The following table contains the proportions of the saponified 

 fat and of the matter soluble in water into which 100 parts of the 

 fat are capable of being changed. 



Human fat. 



Saponified fat 95 



Soluble matter 5 



Fat of the sheep. 



Saponified fat • 95* 1 



Soluble matter 4*9 



Fat of the ox. 



Saponified fat 95 



Soluble matter 5 



Fat of the hog. 



Saponified fat 94-7 



Soluble matter 5*3 



The quantity of soluble matter in these cases was obtained by- 

 calculation from the weight of the saponified fat, because it was 

 not possible to separate completely the former from a portion of 

 water and saline matter which was combined with it. Thus the 

 syrupy fluid, which contained the sweet principle produced by 

 saponification, although evaporated until it began to be volati- 

 lized, always weighed more than the fat had lost of soluble matter; 

 for example, the syrup obtained from human fat weighed 9*4, 

 that from sheep's fat weighed 8, while that from the fat of the 

 ox and the hog each weighed 8'6. 



M. Chevreul next proceeds to a particular examination of the 

 soaps of fat and potash. The following was the method of analy- 



