. 
ON THE TOXIC EFFECT OF DILUTE SOLUTIONS OF 
ACIDS AND SALTS UPON ‘PLANTS: 
Bs DD. HEALD. 
(WITH PLATE VII) | 
1. INTRODUCTION. 
The desire for a deeper and clearer insight into the subject 
of nutrition of plants. has led many botanical investigators to 
endeavor to determine the poisonous or nutritive qualities 
of a large number of compounds. Within the last decade a 
considerable number of papers have appeared dealing with the 
toxic effect of compounds which are generally classed as non- 
nutritive. The majority of these older experiments have been 
along the same line, and so far as known the compounds have 
been prepared by making solutions of a certain per cent. by 
weight. During the last year Kahlenberg and True’ have car- 
ried out numerous experiments with very many inorganic and 
Organic acids and various salts in which a different method was 
employed. In these experiments the solutions were prepared 
according to gram equivalents, and the results obtained are 
extremely interesting both from the chemical and the biological 
Point of view. All of the experiments alluded to were carried 
out with a single plant, Lupinus albus. 
It is important to know whether these results can be con- 
firmed by the use of other plants, which might be expected to 
differ in their reactions; and to this end, at the suggestion of 
Dr. Kahlenberg, the present investigation has been made. ; 
Before taking up the results in detail it may be well to pre- 
sent a few general considerations in regard to plant, or rather 
protoplasmic, poisons. Compounds which have a toxic effect 
Upon animals are generally poisonous to plants, although we 
find different degrees of sensibility to the same compound in 
“Bor. Gaz. a2: 81. 1896. 
#96) 125, 
