138 



Scientific Proceedings (106). 



75 (1535) 



Outline of a classification of the lipoids. 



By W. R. Bloor. 



[From Department of Biochemistry and Pharmacology, University 



of California.] 



At the meeting of the American Society of Biological Chemists 

 in December, 1919, the matter of a classification of the fats and 

 related substances was brought before the members for discussion. 

 It was decided that the available knowledge on the subject was 

 insufficient to justify a classification at that time. While ad- 

 mitting the truth of the conclusion it has seemed to me since, 

 that something might be gained by an attempt at classification, — 

 in clarifying our ideas and in bringing the newer developments 

 in the field into connection with the old — even though the scheme 

 might later have to be radically changed or even abandoned. 

 It is becoming more and more apparent, for example, that the 

 fats and the substances ordinarily grouped under the name of 

 lipoids are so intimately related both chemically and in meta- 

 bolism — all being directly connected with the metabolism of the 

 fatty acids — that they should be considered together, and when 

 so considered they form a group which is believed to be as distinct 

 and well defined as that of the carbohydrates and proteins. 

 The following is an outline of proposed classification: 



The Lipoids. 



The higher fatty acids, their naturally occurring compounds 

 and certain substances found naturally in chemical association 

 with them. 



The group is characterized in general by insolubility in water 

 and solubility in 'fat solvents' — ether, chloroform, benzol, etc. 



Simple Lipoids. 



Esters of the fatty acids with various alcohols. 



Fats. — Esters of the fatty acids with glycerol, (fats which 

 are liquid at ordinary temperatures are called oils.) 



Waxes. — Esters of the fatty acids with alcohols other than 

 glycerol. Beeswax, lanolin, cholesterol oleate. 



