320 IV. WAXES, HIGHER AT.COHOLS, ETC. 



cussed from various viewpoints in recent years, and the reader is referred 

 to the specific articles for more details. The chemical aspects have been 

 periodically reviewed, during the period of rapid development, by a number 

 of masters in the field. These include chapters by Windaus"'^ Rosenheim 

 and King,'"*^ Schoenheimer and Evans, ^°^ Heilbron and Jones, ^"^ Shoppee,^"^ 

 Sobotka and Bloch,"" Koch,^^^ Ruigh,"- Reichstein and Reich, ^^^ and Sarett 

 and Wallis."'' An excellent treatment of the historical aspects developed 

 largely from a physiological standpoint is contained in the review by Bills,"" 

 which includes a discussion of the relationship to vitamin D. Probably the 

 most complete treatment of the subject is afforded in the comprehensive 

 monograph of L. F. and M. Fieser."*^ Another extensive discussion is to be 

 found in the section written by Winterstein and Schon in the monograph of 

 Hefter and Schonfeld"^ on lipids. 



(a) History of Sterols. Cholesterol was the initial compound of this 

 group to be separated and identified. Poulletier"* prepared it from gall- 

 stones (1769). De Fourcroy"^ classified it with spermaceti and "adipocire" 

 because of its wax-like properties. Its true nature was first recognized by 

 Chevreul,^^" who demonstrated that it was unsaponifiable and hence could 

 be differentiated from other wax-like materials. This same worker'-' 

 coined the name "cholesterine" for the product now known as cholesterol, 

 from the derivatives, chole, bile, and stereos, solid. Another milestone in 

 understanding the chemical nature of cholesterol was the discovery by 

 Berthelot'22 that it is an alcohol. This investigator prepared a number of 

 cholesterol esters and anticipated the finding of these compounds in the 

 body, and suggested their relationship to bile acids. However, the term 

 "sterol" did not come into general use"^ until 1911 as a term to include all 

 the animal and plant alcohols of this series. 



105 A. Windaus, Ann. Rev. Biochem., 1, 109-134 (1932). 



106 O. Rosenheim and H. King, Ann. Rev. Biochem., 3, 87-110 (1934). 



107 R. Schoenheimer and E. A. Evans, Jr., Ann. Rev. Biochem., 6, 139-162 (1937). 



108 I. M. Heilbron and E. R. H. Jones, Ann. Rev. Biochem., 9, 135-172 (1940). 

 103 C. W. Shoppee, Ann. Rev. Biochem., 11, 103-150 (1942). 



110 H. Sobotka and E. Bloch, Ann. Rev. Biochem., 12, 45-80 (1943). 



111 F. C. Koch, Ann. Rev. Biochem., 13, 263-294 (1944). 



112 W. L. Ruigh, Ann. Rev. Biochem., 14, 225-262 (1945). 



113 T. Reichstein and H. Reich, Ann. Rev. Biochem., 15, 155-192 (1946). 

 11" L. H. Sarett and E. S. Wallis, Ann. Rev. Biochem., 16, 655-688 (1947). 

 lis C. E. Bills, Ph^jsiol. Revs., 15, 1-97 (1935). 



116 L. F. Fieser and M. Fieser, Natural Products Related to Phenanthrene, 3rd ed.. Rein- 

 hold, New York, 1949. 



117 A. Winterstein and K. Schon, in G. Hefter and H. Schonfeld, Chemie und Tech- 

 nologic der Fette und Fettprodukte, Vol. I, Springer, Vienna, 1936, Chap. IV, pp. 111-144. 



118 Poulletier de la Salle, circa 1769. Cited by de Fourcroy, Ann. chim. phijs. [1], 3, 

 242-252 (1789), and by C. E. Bills, Physiol. Revs., 15, 1 (1935). 



119 De Fourcroy, Ann. chim. phys. [1], 3, 242-252 (1789). 



120 M. E. Chevreul, Ann. chim. phys. [1], 95, 5-50 (1815). 



121 M. E. Chevreul, Ann. chim. phys. [2], 2, 339-372 (1816). 



122 M. Berthelot, Ann. chim. phys. [3], 56, 51-98 (1859). 



