[Vol. 2 



524 



ANNALS OF THE MISSOURI BOTANICAL GARDEN 



determined, with the following results, the figures repre- 



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average green weight of tops in each cu] 



crop unl reated 3.31) 



crop treated with illuminating gas 4.:*8 



crop in oven 1 and 2 hrs. at 6(3-33° C 3.35 



grams 



rams 



grams 



V. Effects of Anesthetic Vapors 



For this work the method used was to place the cultures (in 

 some cases the medium also, in which instances the roots were 

 in the water during exposure, and in other cases only the 

 plants themselves, thus exposing the roots directly to the 

 vapor) under bell jars into which the anesthetics were subse- 

 quently placed. In the case of ether and chloroform a meas- 



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Days 



Fig. 



No. 21, 



1. Conductivity curves of cultures (series 11) in distilled 

 water subsequent to treatment with anesthetics, as follows: 

 ether vapor, 1 minute, roots exposed; No. 22, control — roots exposed 

 under bell jar 1 minute; No. 23, ether vapor, 2 minutes, roots 

 exposed; No. 24, ether vapor, 5 minutes, roots exposed; No. 25, ether 

 vapor, 10 minutes, roots exposed; No. 20, ether vapor, 15 minutes, 

 roots exposed. The plants used were 39 days old. The first reading 

 in each case is of the distilled water before the roots were placed 

 in it. 



ured amount of these agents was placed in an open evaporat- 

 ing dish under the bell jar, and after the treatment the residue 

 was measured to determine the amount which had evaporated ; 

 in the case of the illuminating gas, however, the agent was 

 run in until the air in the bell jar was more or less completely 

 replaced. Where the plants alone were placed under the bell 

 jars they were carefully attached by cheese-cloth bands to the 

 leg of an inverted tripod, over which the bell jar was then 

 placed. 





