SECT. II] FAT METABOLISM 1183 



11-5. Fat Metabolism of Teleostean Eggs 



In the teleostean egg all is different. Tangl, in the course of his 

 series of researches on the energy sources of eggs, had accustomed 

 himself to regard fatty acids as the most usual material of this kind, 

 and he received an unexpected surprise when, with Farkas, he in- 

 vestigated the egg of the trout. Estimating the fatty acid content 

 before fertilisation and at hatching, they noted an unmistakable in- 

 crease, as follows : 



Amounts in miUi- 

 grams per egg Change 



This was confirmed on the eggs of another trout, Savelinus fontinalis, 

 by McGlendon in 19 15, who obtained very similar results, indicating 

 a synthesis of fatty acids during development. These were his results: 



Amounts in milli- 

 grams per egg 



Before After 



Change 



develop- develop- Dry 



ment ment Absolute weight Initial 



Wet weight ... ... ... 62-0 — — — — 



Dry weight ... ... ... 17-0 — — — — 



Fatty acids (direct) ... ... — — — +0-99 +5'57 



Ether extract — — — +1-3 +5*55 



This curious process appeared again in the work of Dakin & 

 Dakin on the egg of the plaice {Pleuronectes platessa) : 



Values in milligrams absolute per 1 00 eggs 



From these figures it appeared that there was an increase of 0-74 mgm. 

 per 100 eggs, or 264 per cent, of the initial store of fatty acids. Hayes, 

 again, working on the eggs of the lumpsucker {Cyclopterus lumpus) found 



