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438 BOTANICAL GAZETTE | DECEMBER 
As a matter of fact, I happen to be the chemist who prepared the normal 
sulfuric acid solution as well as the other solutions used by Dr. True and 
myself,.and the strengths of all the solutions were exactly as indicated in the 
columns of the tables. The results of Kahlenberg and True indicate that 
ivy gram-equivalents. of H,SO, per liter is as toxic as g¢@yo gram-equiva- 
lent of HCl per liter, and not that ¢¢y9 gram-equivalent of H,SO, per liter 
is as toxic as y#y9 gram-equivalent of HCl per liter as Mr. Dandeno states ; 
this shows how much care he used in scrutinizing the tables he attempts to 
criticise. 
Kahlenberg and True have found that a solution containing gdyo of a 
gram-equivalent of H,SO, (7. e. s$%s grams) per liter is as toxic as a solution 
containing ¢d¢os of a gram-equivalent of KHSO, (z. e. @#o%r grams) per liter. 
Since KHSO, contains but one hydrogen atom, which is the active agent 
under consideration, either the term gram-equivalent or gram-molecule might 
be used concerning this substance, for they mean the same thing here; asa 
matter of fact the term gram-equivalent is used in Kahlenberg and True’s 
table. There is no confusion in Kahlenberg and True’s article on this point, 
as Mr. Dandeno thinks. On the bottom of p. 91 of Kahlenberg and True’s 
paper is the statement, “‘ Tables 1 to 5 show that the seedlings just survive in 
a solution that contains gqy;y gram of hydrogen ions per liter,” which might 
have shown Mr. Dandeno that no confusion exists, had he read it with suff- 
cient care. 
To be sure Ostwald in his tables of electrical conductivity expresses the 
concentrations of the solutions in gram-molecules per liter; but this does not 
prevent one from calculating from these tables the degree of dissociation of 
’ a salt in a solution, the strength of which is expressed in gram-equivalents 
per liter, as Mr. Dandeno seems to think. Kahlenberg and True were wel 
aware of the true character of Ostwald’s tables, and in referring to them, and 
in calculating the dissociation from them, they took into consideration the 
fact that the tables are based on gram-molecules per liter. Take the case of 
maleic and fumaric acids of which Mr. Dandeno makes a special point. 
These acids are both dibasic. In Ostwald’s tables we find that when I gram- 
molecule of maleic acid is contained in 2048 liters, the degree of dissociation 
is 98.2 per cent.; and when 1 gram-molecule of fumaric acid is contained in 
2048 liters the degree of dissociation is 78.5 per cent. Now in the case of a 
dibasic acid, a solution containing 1 gram-molecule in 2048 liters is clearly 
identical with a solution containing 1 gram-equivalent in 1024 liters; and so 
when Kahlenberg and True state “as maleic acid at the dilution 1024 is dis- 
sociated 98.2 per cent. and fumaric acid 78.5 per cent. we should expect the 
latter to be less poisonous than the former if the toxic action be dueto H ions 
alone,’ they are perfectly correct. Moreover the tables (58 and 59, p- 115 of 
3 Zeitschrift physik. Chem. #2 380. 
