92 ~ THE MICHIGAN ACADEMY OF SCIENCE. 



*THE RELATION OF MASS ACTION AND THYSICAL AFFINITY 



TO TOXICITY. WITH INCIDENTAL DISCUSSION AS TO 



WHAT EXTENT ELECTROLYTIC DISSOCIATION 



MAY BE INVOLVED. 



J. B, DANDE.XO. 



(Abstract.) 



Experiments were performed with seedlings of corn, lupine, and pea, 

 in such a way as to expose the radicle to the toxic agent for a given 

 time, and then to decide, by a twenty-four hours' immersion in water, 

 whether the reagent had iiermanently inhibited the growth of the 

 radicle. The toxic agent was applied in quantities varying from 1 c.c. 

 up; and a non-chemical body (pure sand) was added to solutions sim- 

 ilarly prepared. 



The results of the experiments, and a summary of the discussion leads 

 to the following: 



(1) Quantity of solution is an important factor in estimating the 

 concentration of a solution which a seedling can withstand; e. g., — corn 

 can live in HCl at n/1024 if the quantity be one c.c, but if the quantity 

 be twenty-five c.c. it can withstand only n/400r). 



The perceptible effect of mass action seems to reach a limit at, or 

 near, a volume of twenty-five c.c, the vital activity of the seedling at 

 this volume being sufficient to neutralize any injurious action which may 

 be due to diffusion. The rate of vital action, therefore, may be repre- 

 sented by the rate of dift'usion at the concentration given for death limit 

 in 25 cc. of solution. 



(2) If a non-chemical body be added to a toxic solution the toxicity 

 is reduced to an amazing extent. 



(3) The theory of electrolytic dissociation receives no support from 

 the physiological side, with the solutions here examined. 



(4) The action causing death to the radicle appears to be a chemical 

 action, Ihe radicle reducing the toxic activity of the solution a certain 

 amount in a given time. 



(5) The size of particles of sand seems to have some influence upon 

 growth indirectly, and upon toxicity directly. 



(G) A chemical analysis of soil can give no definite notion as to the 

 nutrient material available for ])lant support. 

 J. B. Dandexo, Ph. D., Asst. Professor of Botany, 

 Botanical Laboratory, 

 AgTicultural College. 



*This paper appears in full in the Amer. Jour, of Sci. for June, 1904. 



