22. 

 to allo» tho aliaentary tract to become empty. 



The first and tenth seta vers then kept in diatilied water as 

 control* and t v vo other sight put In 10, 20 # 25 and 30 c.c. of HC1 -mi HBr K*de 

 up to 400 CO. with distilled water. Tho cnrbon lioxUe production, whether 



expreeeed «• gra«s par dor or »» psr cont of norte%l, decreased progressively 

 with tho lncroaee in concentration of aoli, except Ir. case of the tadpolon in 30 

 o.e. of HC1 (T*!ble 19, Fig. 39) which showed a decided rlaa. The survivors 



wore allowed to reganer-ita in the aatae concentr \tiona of <*olaa. Table 20 gives 

 the raaulta. Tha HC1 series ahow a progreseive ieoreaae in regeneration 

 (Fig. 30). Xu tha HBr sariaa tha tadpoles in 20tc.c. regenerated .-»ora rapidly 

 than thoaa in 10 c.o, after the seventh day. This ia probably attributable 

 to ehanee aa the tadpoles in 25 c.c. showed greatly -dec roaaad regeneration 

 and survived only eight lays. Figure 31 $lvoe tha rate of regeneration of the 

 HC1 serlee m time neeeeeary to regenerate 25, 30 ani 32.5^ of the amounts re- 

 moved, and the CO^ production of the aaeie tnllviduals ~.s c.c* H^COg par gran 

 of tadpole par d*y. It is provable th«*t for cent of aoretal COg production 

 (Fig. 29) ia tha worn logical tray of representing the effect of w environmental 

 factor upon netabolleie. Hare again (Fig. 31) the curves for various f9r cents 



of regeneration are confooel, showing that far each concentration the relative 

 velocities of the d liferent stages are the sane* 



Tables 21 and 22 give the results of an experiment In which CO^ 

 detern. r*s were «ade Jaily throughout the period of regeneration. Four 



rather larjre tadpoles i»ere used, care being taken to be** theti as nearly alike 

 as possible. The experiitent was begun at an alsoat constant teieperituro of 

 thirteen degrees centigrade, but later was placed at roow taatperature in order 

 to hasten regeneration. The effect of tno aoid in decreasing both the COj 

 production and the regeneration (T*ble 23, Fig. 33) ia pronounced. 



