446 Dandeno — Relation of Mass Action to Toxicity. 



it may be. In each case the toxic action of the solution is 

 reduced ; in the former by neutralization and in the latter by 

 extraction of the harmful element. This is plainly shown in 

 Tables X and XI. Each seedling makes the solution less toxic, 

 as is shown from the fact that on the first day the seedlings 

 lived in a quantity of l cc in the case of both acids, while on 

 the eighth day they lived in a quantity of 12 cc . 



Larger quantities than 25 cc were used, but no difference was 

 noticed. In fact, when two or three seedlings were placed in 

 a beaker (100 cc ) with radicles immersed, it usually happened 

 that they stood the concentration better than when placed 

 singly in vials containing only 25 cc of solution. 



Small quantities, as a rule, gave the most clear-cut reactions, 

 probably because of the fact that diffusion in solutions is so 

 very slow, making it possible for a considerable quantity of 

 the solute or of the ions to lie in a part of the solution too far 

 from the radicle of the seedling, to affect it. But in the case 

 of small quantities, diffusion will enter into the problem to no 

 very great extent, rendering it possible to obtain results which 

 are more nearly accurate from a chemical point of view. 



The actual amount of toxic ions overcome in 24 hours by a 

 seedling of corn with H 2 S0 4 and BLC1 is l cc of nj 1024, giving 

 a result of 1/000x1/1024 = 1/1024000 grams of ionic hydro- 

 gen. This may be expressed in another way: — 1,024,000 seed- 

 lings woifld resist the toxic action produced by one gram of 

 ionic hydrogen. It may be proved absolutely, as indicated in 

 Table II, column A, of a concentration of w/1024. For, if a 

 gram-equivalent solution be diluted to n/\ 024 and divided up 

 into quantities of l cc , and a seedling be placed in each, they 

 would all grow; but if divided up into quantities of 2-J cc , and a 

 seedling placed in each, they would all die. For more dilute 

 solutions, the seedling can live in the presence of a far greater 

 amount of ionic hydrogen, showing that diffusion is remarkably 

 slow and that the action of the mass of the water is consider- 

 able. The number of gram-ions in a solution m/2048 would be 

 half as many per unit of volume ; but the corn seedling lives 

 when submitted to 12 cc of this solution. It ought, however, to 

 withstand only 2 CC , if diffusion were perfect and mass action 

 eliminated. Consequently, the injurious ions in 10 cc of the 

 12 cc used are prevented from acting upon the radicle from 

 the fact that the mass of liquid is great enough to render 

 10/2x1/102400 grams of ionic hydrogen harmless, when in a 

 quantity of 12 cc . This is the condition of affairs with corn for 

 H 2 S0 4 . It is apparently different with IIC1 at the dilution 

 mentioned but similar at the next lower dilution. Where the 

 seedling is particularly sensitive to the solution, as with the 

 pea, there is small difference in relatively great concentra- 



