492 



MINNA E. JEWELL 



Ba(0H)2, hence the addition of substances to the water which 

 will decrease the number of free H ions is beneficial to the tadpoles 

 regardless of titratable acidity. 



Table 6 gives the results of an experiment in which CO2 deter- 

 minations were made daily throughout the period of regeneration. 



TABLE 6 

 Regeneration in HCl 



CO2 production during the period of regeneration 



Four rather large tadpoles were used, care being taken to have 

 them as similar as possible. The experiment was begun at an 

 almost constant temperature of 13°C., but after nineteen days 

 was placed at room temperature in order to hasten regeneration. 

 The effect of the acid in decreasing both the CO2 production and 

 the regeneration is pronounced. 



