38 FATS, OILS, AND WAXES 



hydrolysed. The initial acids to be formed are characterized 

 by a low iodine value, showing that they are saturated. 

 Further, since the Reichert Meissl value is constant and 

 does not vary with the acid number, it is concluded that the 

 acids first formed belong to the higher members of the 

 fatty series. The saturated acids are followed by the un- 

 saturated. Ivanow gives the following scheme to indicate the 

 essential stages in the synthesis of fat in a typical instance 

 such as the seed of flax : 



Carbohydrate < Fat. 



\ Saturated Unsaturated ' 



fatty acid. fatty acid. 



During the germination of oily seeds a reversal of this 

 process takes place. The work of Schmidt, Green,* Le Clerc 

 du Sablon, and others, has shown that the first process is that 

 of hydrolysis which splits the fat into a fatty acid and glycerine, 

 lipase being the active agent. 



Thus in the sunflower Miller f found that less than I per 

 cent of free fatty acid was present in the oil of the cotyledons 

 of the resting seed ; as germination proceeded there was a 

 gradual increase, thus the ether extract of the cotyledons of 

 a seedling in which the plumule was just showing contained 

 30 per cent of fatty acid. 



The presence of the acid may be demonstrated in such 

 germinating seeds, but the same statement does not hold for 

 glycerine, probably because it is translocated with great rapidity, 

 and is quickly transformed. There can, however, be no doubt 

 that this substance is formed because if, for example, castor 

 oil be subjected in vitro to the action of lipase obtained from 

 Ricinus seeds, the presence of glycerine may be detected with 

 ease. 



With regard to other changes which the original fat under- 

 goes during germination, Schmidt found that the iodine number 

 of the unsaturated acids and oils decreased during germin- 

 ation, which indicates that saturation of the acid radicles 

 takes place. This is controverted by von Fiirth, J who found 



* Green : " Proc. Roy. Soc., Lond.," 1890, 48, 370. 



f Miller : " Ann. Bot.," 1910, 24, 693. 



JVon Fiirth: " Hofm. Beitr. Chem. Phys. Path.," 1904, 4. 



