6 ANALYSIS AND ADULTERATIONS OF BUTTER. 



of butter-fat was discovered in that substance by Chevreul. It 

 has since been obtained from a great variety of sources ; thus 

 it was found in the locust bean, in the fruits of the soap 

 tree, and of Gingko biloba, in sour gherkins, in the sauer- 

 kraut of the Germans, in human perspiration, in flesh, in oil 

 of amber, and in cod-liver oil. It occurs in small quantities 

 in some mineral springs, and is formed by the fermentation 

 of sugar, starch, and lactic acid, it thus being usually prepared. 

 It is not found in any animal fat except in butter and cod- 

 liver oil. 



Butyric acid is a colourless liquid, strongly acid, and 

 possessing an odour as of acetic acid and of butter com- 

 bined. Its taste is sour and rancid in the highest degree. It 

 boils at 157 C., and is soluble in water, alcohol, and ether. 

 It may be volatilised and distilled without change or decom- 

 position. 



Caproic acid, C 6 H 12 2 was first found in butter. It also 

 exists in cheese and in cocoa-nut oil. It is a clear and colour- 

 less liquid, sparingly soluble in water, but easily dissolved 

 by alcohol. It boils at 202 C., and possesses a specific 

 gravity of 0'922. 



Caprylic add, C 8 H 16 2 resembles in its physical characters 

 the preceding, with which it is usually found associated. 

 It has but a feeble odour, solidifies at 12 C., boils at 236 C-, 

 and is slightly soluble in water, 126 parts of which at 

 10 C. and 50 parts at 100 C. dissolve one part of the acid. 

 It is quite insoluble in alcohol and ether, and has a specific 

 gravity of 0*911. 



Capric acid, C 10 H 20 2 has been found in butter, cocoa- 

 nut oil, and in fusel oil. It is a white solid crystalline body, 

 melting at 29*5 C., easily soluble in alcohol and ether, but 

 dissolved only with great difficulty in large quantities of 

 boiling water. It is not volatile to any considerable degree. 



The four acids last described were all discovered in butter- 



