﻿1903] 



CHEMICAL STIMULATION 



177 



in 400'''' water, and the smaller bottle contained 22'''^ of the 



N 



10 



solution, and water to 40^"^, The CO3 content of the two bottles 

 must have been practically the same when air had been passing 

 through them over night. 



TABLE XXXllI. 



Salt 



N 



TOT 



*- — "v — ^^ 



N 



1 17 



N 



NaCl 



29^ 



t 4 



35^ 



NaNOg 



* • 



34^ 



58 (too hieh ; cf. XXXV) 





« * 



» 



32 



KCl 



41 



42 



58 





29.4 



48.7 



52 



KNO3 



39 



40.4 



62 





36-4 



« 4 



61 



KsSO^ 



« # 



31 



• w 



N 

 A single comparison of KNO3 and KI, both — , showed the 



same acceleration for eighteen hours at about 2i°C., after which 

 the KI material took a considerable lead and was in large part 

 dead when the experiment ended. 



It appears from this summary of results on K and Na, that 

 the former is decidedly the stronger stimulant. Jacobi (p. 302) 



reports a much greater acceleration by — NaCl than by — 



KCl; but in six experiments, only part of which are repre- 

 sented in the above table, in which KCl or KNO3 was in one 

 bottle and the same concentration of the corresponding Na salt 

 in the other, I have found no single instance in which the K 

 salt failed to produce the greater effect. Kosinski (p. 141 )' 



at the other extreme, concludes that while KNC and 



K,SO 



accelerate the respiration of Aspergillus, 



NaCl does not do 



at all. My results on the respiration harmonize perfectly 

 with the greater toxicity of K. True*^ rates the relative toxicity 

 of K and Na to Spirogyra at 10:6. It seems to be about the 

 same to Elodea. 



It has been found by a number of observers that chlorids 



"^ R. H. True, The physiological action of certain plasmolysing agents. Box, 



Gaz. 26:407-416. 1898. 



