864 GENERAL METABOLISM [pt. iii 



He pointed out that a continual rise took place, a change from the 

 acid side to the alkaUne side, and suggested that it was an approach 

 towards the isoelectric point of the tissue proteins. 



Much more satisfactory was the work of Buytendijk & Woerde- 

 mann with their antimony micro-electrodes. Using them in the 

 way described above, they obtained the following results : 



Some difference was made according to how long the estimations 

 were done after the cessation of the circulation. On the whole, the 

 values for the 13th day were lower than those for the 7th day, 

 but higher than the figure ob- 



Cohn.Mirsky ^ Porosovski 



(Glass electrode) 



) redoced 

 » oxygenated 



t 



tained by Murray and Guey- 

 lard & Portier. 



Another aspect of this work 

 is the />H of embryonic blood. 

 Murray made no estimations 

 of this, but Cohn & Mirsky 

 and Cohn, Mirsky & Poro- 

 sovski afterwards made com- 

 plete measurements for the 

 chick embryo at all stages by ' pjg 217. 



means of the glass electrode. 



Between the 6th and the 8th days the blood was relatively acid, and 

 from the 9th to the 15th days there was a plateau just on the alkaline 

 side of neutrality, after which the rise towards the alkaHne side 

 was continued, to reach the adult level at the time of hatching. 

 Experiments on the blood of the developing cat embryo gave very 

 similar results. It is obvious that the course taken by the blood />H in 

 the chick agrees closely with that of the /'H of the yolk. There is also 



