260 M. Chevrcul on Fatty Bodies, and [Oct, 



phrases when speaking of the different bodies that he has been 

 describing, as supposing that their nature was not sufficiently 

 determined. He now, however, conceives that he may apply 

 specific names to them, which will both be more commodious, 

 and, at the same time, by being made appropriate, will point out 

 the relation which these bodies bear to each other. The follow- 

 ing is the nomenclature which will be hereafter adopted. The 

 crystalline matter of human biliary calculi is named cholesterine, 

 from the Greek words x°M bile, and repso; solid ; spermaceti is 

 named cetine, from xtjtoc, a whale ; the fatty substance and the 

 oily substance, described in the third memoir, are named respect- 

 ively stearine and ela'iiie, from the words rsatg fat, and e*«iov oil ; 

 margarine and the fluid fat are named margaric acid and oleic 

 acid, while the term cetic acid is applied to what was named 

 saponified spermaceti. The margarates, o/eates, and cetates, will 

 be the generic names of the soaps or combinations which these 

 acids are capable of forming by their union with salifiable bases. 



The author begins his examination of the different kinds of 

 fat by giving an account of the different properties which they 

 exhibit in their entire undecomposed state. 



Two portions of human fat were examined, one taken from the 

 kidney the other from the thigh ; after some time they both 

 of them manifested a tendency to separate into two distinct sub- 

 stances, one of a solid and the other of a fluid consistence ; the 

 two portions differed in tbeir fluidity and their melting point. 

 These variations depend upon the different proportions of stea- 

 rine and elai'ne ; for the concrete part of fat is a combination of 

 the two with an excess of stearine, and the fluid part is a combi- 

 nation with an excess of elai'ne. The fat from the other animals 

 was then examined, principally with respect to their melting 

 point and their solubility in alcohol ; the melting point was not 

 always the same in the fat of the same species of animal. When 

 portions of the fat of different sheep are melted separately at the 

 temperature of 122°, in some specimens the thermometer 

 descends to 9S - 5° and rises again to 102°, while in others it 

 descends to 104°, and rises again to 106°. A thermometer 

 plunged into the fat of the ox melted at 122°, descended to 98*5°, 

 and rose again to 102°. When the fat of the jaguar was melted 

 at 104°, the thermometer descended to 84°, and rose again to 

 about 85° ; but a considerable portion of the fat still remained in 

 a fluid state. With respect to the solubility of the different kinds 

 of fat in alcohol, it was found that 100 parts of it dissolved 2-48 

 parts of human fat, 2*26 parts of sheep's fat, 2 - 52 parts of the 

 fat of the ox, 2-18 parts of the fat of the jaguar, and about 

 2*8 parts of the fat of the hog. 



M. Chevreul next examines the change which is produced in 

 the different kinds of fat respectively by the action of potash. 

 All the kinds of fat are capable of being perfectly saponified, 

 when excluded from the contact of the air ; in all of them there 



