1915] 



MERRILL — ELECTROLYTIC DETERMINATION OF EXOSMOSIS 



541 



70 



65 



60 





55 



V 



3 



50 



45 





5 



40 



35 



8 



3 30 

 > 

 25 



20 



15 



1 



2 



3 



4 



5 



6 



7 



Da vs 



Fig. 10. 



Conductivity curves of cultures (series 14) in distilled 

 water subsequent to treatment, as follows: No. 29, temperature of 

 92°C, 2 minutes, roots exposed; No. 30, temperature of 92°C, 1 

 minute, roots exposed; No. 31, temperature of 92 °C, 4 minutes, roots 

 exposed; No. 32, temperature of 92°C, 2 minutes, roots in tumbler; 

 No. 33, temperature of 92 °C, 4 minutes, roots in tumbler; No. 34, 

 control — roots in tumbler at laboratory temperature. The plants were 

 29 days old at the time of treatment. The first reading was taken in 

 each case after the roots had been in the distilled water for the follow- 

 ing respective periods (the cultures whose roots were in tumblers 

 during the treatment were likewise in the distilled water during that 

 time) : No. 29, 2 hours and 47 minutes; No. 30, 2 hours and 48 

 minutes; No. 31, 2 hours and 44 minutes; No. 32, 2 hours and 45 

 minutes; No. 33, 2 hours and 46 minutes; No. 34, 2 hours and 46 

 minutes. 



duced less exosmosis at the beginning than was the case in No. 

 29, but finally caused more. The same irregularity is also 



noticed in Nos. 32 and 33. These 



gularities near the 



boundary line of endurance have been discussed above 



The 



tops of Nos. 29-33 were killed by the treatment, but the roots 

 of all remained practically normal in appearance excer>t in No. 



