LIPIDS PRESENT IN SKIN AND ITS APPENDAGES 783 



the observations of Eckstein 425 indicate that the same phenomenon applies 

 to man. The cholesterol content of the fur of the rabbit was found to vary 

 with the season, being higher in the fall and winter and lower in spring and 

 summer. 424 No difference in the amount of this component was attribut- 

 able to color, although curly hair had a lower cholesterol content than did 

 straight hair. 



In addition to the presence of cholesterol in hair, the so-called "iso- 

 cholesterol" has likewise been reported as a component of this fat. As 

 early as 1872, Schulze 426-428 described this cholesterol-like component 

 which is present in lanolin or wool grease. It has likewise been identified 

 in the petroleum ether extract of merino wool. 429 Isocholesterol is now 

 known to consist of at least two separate compounds, 430 which are re- 

 ferred to as agnosterol and lanosterol. Agnosterol has the empirical 

 formula, C30H47OH, while that for lanosterol is C3JH49OH. Neither of 

 these products is isomeric with cholesterol. In fact, they do not possess 

 the steroid nucleus. They belong to the triterpene group. The names, 

 "isocholesterol," lanosterol, and agnosterol, are therefore misleading and 

 should not be used to describe these compounds. In addition to cholesterol 

 and the triterpenes, two higher aliphatic alcohols, cetyl and ceryl alcohols, 

 were reported by Drummond and Baker 429 to be present in the lipids ex- 

 tracted from merino wool. However, no glycerol was found in the wool 

 fat. 



The fatty acids in wool wax are characteristic of this tissue. Weit- 

 kamp 431 classified the fatty acids in wool wax into the following categories: 

 (1) normal saturated acids; (2) 2-hydroxy-acids ; (8) iso- (or branched- 

 chain) acids corresponding to the general formula, CH 3 CH(CH 3 )(CH 2 ) 2re - 

 COOH, in which n is 3 to 11 inclusive; and (4) anteiso-acids with the gen- 

 eral structure, CH 3 CH 2 CH(CH 3 )(CH 2 ) 2n COOH, in which n is 2 to 13 

 inclusive. 



Group 1 comprises not only palmitic and stearic acid, but also the C 2 6 

 acid, cerotic acid. 429 Acids identified in Group 2 include 2-hydroxy- 

 myristic, 431 2-hydroxypalmitic, 431,432 and lanopalmic acid, 432-434 which is an 



426 H. C. Eckstein, J. Biol. Chem., 73, 363-369 (1927). 



426 E. Schulze, Ber., 5, 1075-1078 (1872). 



427 E. Schulze, Ber., 6, 251-254 (1873). 



428 E. Schulze, /. prakt. Chem. [n.s.], 7, 163-178 (1873). 



429 J. C. Drummond and L. C. Baker, J. Soc. Chem. Ind., 48, 232-238T (1929). 



430 A. Windaus and R. Tschesche, Z. physiol. Chem., 190, 51-61 (1930). 



431 A. W. Weitkamp, J. Am. Chem. Soc, 67, 447-454 (1945). 



432 T. Kuwata, J. Am. Chem. Soc, 60, 559-560 (1938). 



433 E. Darmstaedter and J. Lifschutz, Ber., 29, 1474-1477, 2890-2900 (1896). 



434 E. E. U. Abraham and T. P. Hilditch, J". Soc. Chem. Ind., 54, 398-404T (1935). 



