Fig. 5 Graph showing the regeneration of tadpoles in increasing concentra- 

 tions of NaaCOa, NaHCOs, and mixtures of NaaCOs and NaHCOs. Each 

 line, average regeneration of four tadpoles; ordinate, per cent regenerated; 

 abscissa, time in days; solid lines, distilled-water controls; doffed Knes, NaaCOs; 

 dash lines, NaHCOa; alternate dot and dash lines, mixed solutions; numbers at 

 end of lines, cc. 0.01 molecular salt solution in 200 cc. of solution used. Where 

 both salts are used, the first number represents the amount of Na2C03. Note 

 that no definite effect of the salt appears until 30 cc. of the Na2C03 or 120 cc. of 

 NaHCOa has been added, and that the effect of 45 cc. Na2C03 is practically un- 

 changed by the addition of 15 cc. NaHCOs. 



Fig. 6 Graph showing the regeneration of tadpoles in increasing concentra- 

 tions of H3PO4. Dotted line, control; ordinate, per cent regenerated; abscissa, 

 time in days; numbers at ends of curves, cc. 0.01 mol. H3PO4 in 200 cc. of solution. 

 Compare with figures 13, 15, and 17, representing regeneration in corresponding 

 concentrations of HNO3, HBr, and H2SO4. 



Fig. 7 Graph showing the regeneration of tadpoles in increasing concentra- 

 tions of KOH. Ordinate, per cent regenerated; abscissa, time in days; numbers 

 at ends of curves, cc. O.OIN KOH in 400 cc. of solution. The CO2 production of 

 these tadpoles during the first twenty-four days of regeneration is shown in 

 figures 3 and 8. Tadpoles in higher concentrations died without regeneration. 

 From data of table 3. 



Fig. 8 Graph showing the regeneration (solid lines) and CO2 production 

 (dotted lines) of the tadpoles whose regeneration curves are shown in figure 7. 

 Ordinate, concentration as cc. O.OIN KOH in 400 cc. of solution; abscissa for 

 regeneration, time in days, for CO2 production, GO2 produced as cc. O.OIN H2CO3 

 per gram per day; numbers at ends of regeneration curves, per cent regenerated. 

 Note the correlation between retardation of regeneration and increase in CO2 

 production. From data of table 3. 



477 



