862 



GENERAL METABOLISM 



[PT. Ill 



figures, does not cover, as it stands, those of Gueylard & Portier, 

 still less those of Friedheim and of Yaoi. Murray called attention, 

 however, to other factors which will obviously have to be considered 

 with relation to the pH. of the embryonic cells, i.e. the functional 

 efficiency of the systems of the organism, such as the circulation, 

 whose function it is to remove the carbon dioxide produced in 



lisys 



to U \Z 13 14 

 Ir.cub8>Uor> a^ 



Fig. 2 1 6. 



metabolism, and secondly the process of ossification, which may 

 affect the concentration of carbonates in the tissues. Since the 

 metabohc rate decreases with age, it alone can hardly be held 

 responsible for the increasing acidity. Cohn & Wile showed that 

 during the early part of development there is a marked increase 

 in the rate and regularity of the cardiac contraction, which might 

 explain the apparent constancy of the tissue />H before the loth day. 

 Murray related the S-shaped curve of his j&H data to the gradient 

 existing between the carbonates in the shell and in the bones, and 



