II54 THE METABOLISM OF NUGLEIN AND [pt. iii 



descends from ii to 4 in just over 10 days, but the pig's N.P.R. 

 takes 70 days to descend from 8 to 4. "La hauteur du potentiel 

 reaHse au moment de la 'mise 



, ,1 11 , 1 , lOr- LeBreton 8c,Schaeffer N.P.R 



en charge des cellules de la ^ 

 blastula ne determinerait-elle 

 pas le regime de decharge ul- 

 terieurement realise pendant le 

 developpement?" said LeBre- 

 ton & Schaeffer. "La decharge 

 se ferait d'autant plus vite que 

 lavaleurinitialeduN.P.R.serait 

 plus elevee." It is as yet too 

 early to say what fruit, if any, 

 this interesting suggestion will 

 bear, but it gains interest from 

 Rubner's well-known table, 

 which shows that the intensity 

 of chemical transformations is 

 greater the smaller the animal and the shorter its gestation time. 

 This subject has already been discussed in some detail in Section 2. 



.length 10 (mouse) 20 



Fig- 351' 



LeBreton & Schaeffer also pointed out the resemblance between the 

 fall of N.P.R. and metabolic rate (compare Fig. 349 with Fig. 143). 

 From the figures now at their disposal LeBreton & Schaeffer were 

 able to calculate the intensity of manufacture of purine nitrogen by the 

 embryo. Smoothing their data for daily increments, they expressed 



