GOAT FAT HUMAN FAT. 137 



is known in this country. It resembles ox fat, but is whiter. 

 When fresh it has hardly any smell. Some varieties of it melt 

 at 100 ; others not till 104, or even 106. It dissolves in 44 

 times its weight of boiling alcohol of 0-821 specific gravity. 



Its stearin is white and without lustre. It begins to solidify 

 at 99^, and the temperature then rises to 111. On congealing 

 it crystallizes imperfectly. It is translucent. One hundred parts 

 of boiling absolute alcohol dissolve 16-09 of it. The elain of mut- 

 ton suet is colourless, has a slight odour of mutton, and a specific 

 gravity of 0'913. One hundred parts of absolute alcohol dis- 

 solve 80 parts of it at the temperature of 167. 



4. GOAT FAT. 



This fat resembles that of the ox, but it has a peculiar and dis- 

 agreeable smell, similar to that of the animal. It is owing to the 

 presence of a peculiar oily matter to which Chevreul has given 

 the name of hircin, and which has been very imperfectly examin- 

 ed. It exists also in small quantity in mutton suet. It is liquid, 

 and is found in the elain when goat fat is separated into elain 

 and stearin. Though hircin has not yet been obtained se- 

 parate from elain, Chevreul succeeded in obtaining hircic acid, 

 which is presumed to be one of the constituents of hircin. 

 He obtained it in the following way : Four parts of goat fat 

 were saponified by digestion in one part of hydrate of potash 

 dissolved in four parts of water. The soap is decomposed by 

 phosphoric or tartaric acid. The fatty acids are separated and 

 washed, and the washings mixed with the acid residue of the 

 decomposed soap. This liquid is distilled.* The liquor that 

 passes over contains the hircic acid. Saturate it with carbo- 

 nate of barytes and evaporate to dryness, and decompose by dis- 

 tilling it with equal weights of sulphuric acid and water. The 

 hircic acid will be found swimming on the water in the receiver 

 under the form of a colourless volatile oil. 



5. HUMAN FAT. 



This fat is softer than either ox fat or mutton suet. It has a 

 yellow colour, and its melting point seems to vary. Chevreul 

 found fat from the kidney, when melted at 104, begin to con- 

 geal at 77. At 75^ it was semifluid, and at 62| it was con- 



* If the matter in the recipient leaves any stain on platinum foil when eva- 

 porated, it must be distilled again. 



