PHYSIOLOGY 39 



by the possession of fats rich in acids of a specific series. 

 Thus the oil of hemp seed is rich in acids of the unsaturated 

 linolenic series, whilst poppy-seed oil is rich in acids of the 

 saturated fatty acid series. 



By ascertaining the iodine and other values of the fats of 

 these seeds at different periods of germination, it was found 

 that the acids disappeared in the sequence linolenic, linolic, 

 oleic, and, finally, palmitic ; in other words, the acids were 

 consumed at a rate inversely proportional to their degree of 

 saturation. 



Ivanow considers that the fall in the iodine value of the 

 fats is due rather to the rapidity with which the more un- 

 saturated fatty acids are used up in the formation of carbo- 

 hydrates rather than to their oxidation. He further found 

 that the saturated fatty acids not uncommonly exist in a free 

 state whilst the unsaturated acids occur in the form of 

 glycerides. 



Von Fiirth * also found that during germination of Ricinus, 

 the acetyl value decreased from 87-5 in the resting seed to 50-5 

 in the young seedling, from which he concluded that the normal 

 fatty acid does not change into hydroxy fatty acid. Also, he 

 could find no proof of the fatty acid breaking down into 

 simpler substances as indicated by the molecular weight re- 

 maining practically constant. 



This hydrolysis is the first action, but it is not the final one 

 since carbohydrates quickly appear during the germination of 

 such seeds. Since the days of de Saussure, who was the first 

 to draw attention to this phenomenon, much evidence relative 

 to this carbohydrate formation has accumulated. 



In the case of Ricinus le Clerc du Sablon found that the 

 resting seed contained 69 per cent of oil and 4 per cent of 

 sugar, but in a seedling 1 1 cm. high the oil had fallen to 1 1 per 

 cent and the sugar had risen to 14 per cent. It was further 

 found that the sugar contained in the resting seed has a slight 

 excess of non-reducing sugar, which increased more rapidly 

 than the reducing sugar ; finally, how^ever, the latter variety 

 preponderated. 



* hoc, cit. 



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