MAE IAN IE WIN 



215 



Frog Eggs. 



In order to check the above results, frog eggs in the blastopore 

 stage were chosen. The CO2 output of the jelly (free from any traces 

 of eggs) was first tested. It was found that in the time required for 



Rate 

 180—1 



I0 



lOOr 



o- 



eOMi n. 



Fig. 4. Curves showing the effect of 7.3 per cent ether (Curve A) on the CO2 

 production of frog eggs, and the control in tap water (Curve B, dotted line). 

 The normal rate is taken as 100 per cent. The point marked on the abscissa 

 indicates the beginning of exposure to ether for Curve A; previous to this the 

 material was in tap water (horizontal part of curves). The normal rate (which is 

 taken as 100 per cent) corresponds to a change from pH 8.0 to pH 7.7 in 157 

 seconds for Curve A and in 142 seconds for Curve B. Each curve represents an 

 average of six experiments. Probable error less than 2.5 per cent of the mean. 



the experiments, no appreciable change in the pH value took place, 

 thus proving that the jelly contains no organisms respiring sufficiently 

 to interfere with the accuracy of the experiments. Fig. 4, Curve A, 

 shows a 44 per cent retardation, followed by an increase in the rate 

 of the CO2 output. There was no disintegration of any portion of the 



