SECT. II] FAT METABOLISM 1177 



between fat and nitrogen depicted in Fig. 368 could be expressed in 

 terms of a ratio. This Bialascewicz & Mincovna did, as follows : 



Hours from Milligrams fatty acid in one larva/ 



fertilisation Milligrams nitrogen in one larva 



o 3-61 



72 3-96 



96 4-26 



140 4-13 



143 4-07 



164 3-49 



239 2-86 



284 2-50 



The ratio tends to rise until hatching because the denominator is 

 decreasing while the numerator is remaining constant, but in the 

 later stages the numerator falls more rapidly than the denominator, 

 so that the ratio falls. 



Faure-Fremiet & Dragoiu studied the iodine value of the fatty 

 acids of the frog's egg, as did Parnas & Krasinska. But again there 

 was a certain contradiction, for whereas the Polish investigators only 

 found a diminution of 2 units, the French ones found a diminution 

 of 10 units. Faure-Fremiet & Dragoiu calculated that at the begin- 

 ning of development 8o-8i per cent, of the total fatty acids were 

 unsaturated (i double bond) and at the end (hatching) only 74-14 

 per cent. By multiplying the lipoid phosphorus by the coefficient 

 25-75, the percentages of phosphatide fatty acids were found, and 

 this fell from 25-13 to 20-0 per cent. One embryo lost up to hatching, 

 they found, 0-192 mgm. of unsaturated acids, and 0-06 mgm. of 

 phosphatide fatty acid, but it must be remembered that none of the 

 other workers found any loss of fat before hatching. 



Barthelemy & Bonnet carried out their experiments at different 

 temperatures, in order to see whether the rapidity of development 

 would exercise any influence upon the amount of fatty acids lost 

 throughout the whole period. Their results were as follows: 



showing that, however much the development may be speeded up, or 

 damped down, the same amount of fatty acids have to be combusted. 

 Moreover, the ratio of fat lost to nitrogen lost is identical, and compares 

 in an interesting way with the ratio of Bialascewicz & Mincovna for 



