Dandeno — Relation of Mass Action to Toxicity. 449 



reverse. Ionization may take place, but a further reaction 

 must be assumed in order to account for the phenomena 

 referred to, both chemical and physiological. 



In order to test the effects of a foreign body upon the solute, 

 pure clean sand (silica) was mixed with the solution, and the 

 radicle immersed in the mixture. The vials were of similar 

 proportions to those used in the liquid tests. The actual net 

 volume of the sand employed was from 5 to 8 CC , and of liquid 

 3-J cc to 6 CC . Each seedling was exposed two days to the mix- 

 ture, and afterwards tested for further growth in water. One 

 reason for exposing two days instead of one — which was done 

 with the liquid tests — was to make absolutely certain that what- 

 ever deductions in regard to power to resist the toxic reagent, 

 should be on the safe side, because some seedlings can endure 

 a solution for one day when they could not for two days. 



In column A, under the given concentration, is placed the 

 average number of mm. the radicle grew in length during forty- 

 eight hours ; and in column B the average number of mm. the 

 same seedling grew when immersed in water after being 

 removed from the mixture (solution with sand). In one respect, 

 therefore, the test was a severer one than when the seedlings 

 were immersed in the liquid, because they were exposed to the 

 reagent twice as long. 



Il.a, H 2 S0 4 . 



n/256 n/512 n/1024 



A B A B A B 



Pea 14 8 6 10 



Lupipe... 13 10 13 3 



Corn 3 22 29 25 15 



Ill.a, HC1. 



w/51 2 n/1024: 



A B A B 



Pea 6 2 27 10 



Lupine 4 5 24 6 



Com 29 17 35- 15 



IY.a, H 2 C0 3 . 



n/vn 



A B 

 Pea ' 8 9 



V.a, CuS0 4 . 



n/2048 n/4096 n/8192 n/16484 



AB AB AB AB 



Pea 2 4 3 4 7 28 17 



Lupine 7 5 6 10 3 13 14 



Corn 2 16 5 23 10 3 4 



