i66 



FAT METABOLISM 



[PT. Ill 



fat must be that during that period it is used for other purposes than 

 combustion. If the discrepancy is not simply an error due to imperfect 

 technique, there is every probabihty that at this period the missing 

 fat is transformed into carbohydrate, for a coincident increase in 

 total carbohydrate occurs. This subject has been discussed in the 

 Section on carbohydrate metabolism, to which reference may be 

 made (pp. 1016-1018). 



Table 168. 



Day 



2150 



We may now consider the growth of the fatty substances in the 

 embryonic body. As Fig. 36 1 shows, there is a considerable divergence 

 in the absolute value of the figures, but this is no doubt due to the 

 various methods used, as will be shown below. One point of im- 

 portance, however, emerges from this group of curves, namely, the 

 inflection which they all possess about the 14th day. This corre- 

 sponds with all that we know about the absorption intensity of fatty 

 substances by the embryo (see Fig. 251), and supports the conclusion 

 that there is a definite awakening of fat metabolism towards the 

 end of development. Another closely related fact is the percentage 

 constitution of the embryo, shown in Fig. 244, which indicates an 



