﻿i68 



BOTANICAL GAZETTE 



[march 



TABLE XXII 



Dilution 



Acceleration, 

 Per Cent 



Dilution 



Accelen-^tionj 

 Per Cent 



2000 



5000 



lOOOO 



1045 

 700 

 224 



20000 

 40000 

 80000 



52 



47 

 



The next table shows the action of several concentrations of 



mercury 



TABLE XXIII. 

 January 23. Tests of HgCl 



Time 



Experiment 



10 : 28-2:04 

 2:04 

 2: 04-7: 46 



M 



160000 



7:46 



7:46- 



11:34- 

 II : 16 



M 



80000 



11:34 



II :i6 (11. 7 hrs.) 



A. M. Exp. alive 



1:58?. M. 



1:58-2:58 

 2 :5s 



M 



lOOOO 



Exp. culture 



0.029 

 HgCIg in exp. b 



0-035 



HgClg in control 



. 037 



0.027 



and sound. Co 



unsound. 



HgClg in exp. 

 bottle. 



0.235 

 practically dead. 



Control 



0.033 



ottle. 



0.027 



bottle. 



0.039 



0.032 



ntrol mostly alive, 



M in control 

 1000 bottle. 

 0.685 

 Control dead. 



\ 



The solutions were poured off to determine the CO^ in them, 

 and to investigate the post-mortal ** respiration'' similar solu- 

 tions made up with tap water were put on the dead Elodea in 

 the bottles. This was followed by practically the same evolu- 

 tion of CO2 as when the solutions were first applied; which 

 seemed to show that the substance from which the COg was 

 driven off was not exhausted enough to interfere with the reac- 

 tion. In this connection it was assumed that the evolution of 

 COg gradually slackened under the influence of an individual 

 dose of poison because the mercury entered into combination 

 and ceased to act. The material was then devoted to a deter- 

 mination of how much COg might be driven from it by an indef- 

 initely repeated renewal of the dose of HgClg. When this had 

 gone on long enough to become monotonous, I varied it by apply- 

 ing the same amount of HgCL in less water, making it more 



