120 OLEIC ACID. NEUTRAL FATS. 



stearic, or of the free acids themselves. 1 Practically nothing is 

 definitely known as to the agencies and mode of this conversion. 

 It may be the result of a purely chemical change, or perhaps it is 

 more probably due to the action of some micro-organism. 2 On 

 either view of its formation the occurrence of adipocire is of 

 extreme interest as showing a possible direct formation of the 

 higher fatty acids and hence of fats from proteids. It is however 

 supposed by some authors that the adipocire is formed entirely 

 by change and aggregation from the fats present in the tissues at 

 death. 3 This view is probably incorrect. 



II. ACIDS OF THE OLEIC (ACRYLIC) SERIES. C^^.COOH 

 (monobasic). 



The acids of this series bear the same relationship to the ole- 

 fines (C 2 H 4 ) that those of the acetic do to the paraffins (CH 4 ). 

 Some of the higher members of the series are found as glycerin 

 compounds in various fats. 



They bear an interesting relation to the acids of the acetic series, 

 breaking up when heated with caustic potash into acetic acid and 

 some other member of the same series : thus, 



Oleic acid. Potassium acetate. Potassium palmitate. 



Ci 7 H 33 .COOH-h2KHO= KC 2 H 3 2 + KC 16 H 31 2 +IL. 



Oleic acid. C 17 H 33 . COOH. 



This is the only acid of the series which is physiologically im- 

 portant. It is found united with glycerin in all the fats of the 

 human body. 



When pure it is, at ordinary temperatures, a colourless, odour- 

 less, tasteless, oily liquid, solidifying at 4 C. to a crystalline 

 mass. Insoluble in water, it is soluble in alcohol and in ether. 

 It cannot be distilled without decomposition. It readily forms 

 with potassium and sodium hydroxide soaps which are soluble in 

 water : its compounds with most other bases are insoluble. It 

 may be distinguished from the acids of the acetic series by its 

 reaction with nitrous acid which converts it into a solid (elaidic 

 acid) and by the changes it undergoes when exposed to the air. 

 It may be converted into stearic acid 



C 17 H 33 . COOH + H 2 = C 17 H 35 . COOH. 



THE NEUTRAL FATS. 



These may be considered as ethereal salts formed by replacing 

 the exchangeable atoms of hydrogen in the triatomic alcohol 



1 Ebert, Ber. d. d. chem. Gesell. Bd. vnr. (1875), S. 775. 



2 Kratter, Zt. f. Biol. Bd. xvi. (1880), S. 455. Lehmann, Sitzb. d. nhus.-med. 

 Gesell. Wiirzburg, 1888, S. 19. 



3 Zillner, Viertelj.f. ger. Med. u. off. Sanhatsw. (N.F.) Bd. XLIV. (1885), S. 1. 



