36 



METABOLISM IN CHANGED CEREBRAL ACTIVITY 



constant for each nucleus in the somatic tissues of any given species 

 and is a measure of the number of cells (Boivin et aL, 1948; 

 Vendrely and Vendrely, 1948, 1949). Thus the relatively constant 

 ratio of phosphocreatine to desoxyribonucleic acid indicates that 

 the quantity per cell was unchanged throughout this period of 

 development. Similar results were obtained for the quantities of 



-? 







1-6 



1-2 



0-8 



0-4 



30 

 20 

 1-0 



60 

 50 

 40 



30 

 20 



0-4 

 0-3 

 0-2 



^•\/ 



J L 



21 30 



Days after birth 



36 



.L..J L_ 



60 



Fig. 6. The quantities of phosphocreatine in rat brain during 



development and growth. Data from Mandel et aL (1953). 



Animals were decapitated and the heads allowed to fall into 



liquid nitrogen before analysis. 



adenosine triphosphate. In the guinea pig, changes analogous 

 to these occur during foetal life (Flexner and Flexner, 1950). 

 Foetuses were removed under general anaesthesia, and immersed 

 in liquid nitrogen while the umbilical circulation was still intact 

 and in good condition. Here also calculation of the quantities of 

 phosphocreatine and adenosine triphosphate in terms of concen- 

 tration/unit weight showed that little if any change occurred from 

 the 30th day of gestation to birth on the 66th day. On the other 



