480 



MINNA E. JEWELL 



Fig. 9 Graph showing the regeneration of tadpoles in increasing concentra- 

 tions of KOH. Each line, average regeneration of five tadpoles; ordinate, per 

 cent regenerated; abscissa, time in days; numbers at ends of curves, cc. O.OIN 

 KOH in 400 cc. solution. The CO2 production of these tadpoles is compared to 

 their rate of regeneration in figure 11. Note the apparently beneficial effect of 

 10 cc. of KOH. This is probably due to neutralization of CO2 produced by the 

 tadpoles, as the hydrogen ion concentration of this solution was changed from 

 pH 9 to pH 6.7 within the forty-eight hours elapsing between renewing of the 

 solution. 



Fig. 10 Graph showing the regeneration of tadpoles in increasing concentra- 

 tions of Ca(0H)2. Plotted as figure 9. The CO2 production of these tadpoles 

 is compared to the retardation of regeneration in figure 12. As in figure 9, the 

 lower concentrations appear to have had beneficial effects. 



Fig. 11 Graph showing the per cent of regeneration (solid lines) and per 

 cent of normal CO2 production (first dotted line) and average CO2 produced per 

 gram of tadpole per day (second dotted line) in increasing concentrations of 

 KOH of the tadpoles whose curves of regeneration are shown in figure 9. Ordi- 

 nate, concentration as cc. O.OIN KOH in 400 cc. of solution; abscissa for per cent 

 regenerated, time in days; abscissa for per cent CO2 produced, per cent of normal 

 CO2 produced in distilled water; CO2 per gram per day, cc. O.OIN H2CO3. Note 

 that whether CO2 production be expressed as per cent of the normal CO2 pro- 

 duction, previously determined for the same tadpoles in distilled water, or as 



