FATS AND OILS, WAXES, AND LIPOIDS 139 



equation to represent the oxidation of oleic acid into starch, sug- 

 gested by Detmer, is interesting as a suggestion of how much 

 oxygen is required and how much heat would be liberated by such a 

 transformation : 



Complete oxidation of oleic acid to the final end-products, 

 carbon dioxide and water, would require much more oxygen, thus: 



Ci 8 H 3 4O 2 +510 = 18CO 2 +17H 2 O. 



Hence, Detmer's reaction would yield only approximately 

 one-half the total energy available in the acid; but it does indicate 

 the possibility of redevelopment of fatty acids or fats from the 

 unoxidized carbohydrate material which remains in the equation. 

 Moreover, there is abundant evidence to show that, in both animal 

 and plant tissues, energy changes are brought about chiefly by 

 the transformation of fats into carbohydrates and vice versa. 



Many different hypotheses have been put forward concerning 

 the mode of transformation of fats into carbohydrates, and the 

 changes which take place in oily seeds during their germination 

 have been carefully studied by many investigators. The follow- 

 ing seem to be fairly well established facts. First, that fats as 

 such may be translocated from cell to cell, since cell-walls and cell 

 protoplasm seem to be permeable to oil if it is a sufficiently fine 

 emulsion; or they may be hydrolyzed into glycerol and fatty 

 acids and translocated from cell to cell in these forms and recom- 

 bined into fats in the new location. Second, that fats are formed 

 from glucose in some plants, from sucrose and from starch in 

 others, and from mannite and similar compounds in still other 

 species. Third, that in germination the fatty acids are used up 

 in the order of their degree of unsaturation, those which contain 

 the largest number of double-bond linkages being used first, and 

 the saturated acids last of all. Fourth, that the sugar produced 

 by the oxidation of fats is derived either from the glycerol or from 

 the fatty acids of the fat, depending upon the nature of the latter. 

 If the fat is saturated, the glycerine is converted into sugar while 

 the fatty acids are oxidized; but if the fat contains large propor- 

 tions of unsaturated acids, these contribute to the formation 

 of sugar. 



