﻿OF THE STATE ENTOMOLOGIST. 11 



goes, therefore, there is nothing to fear from the judicious use of the 

 mineral. Let us then consider, from the best authority, what are the 

 effects of its use as at present recommended : First, on the plant itself; 

 second, on the soil; third, on man, indirectly, either through the soil 

 or through the plant. 



Its Influence on the Plant. — Practically the effect of sprinkling 

 a plant with Paris Green, will depend very much on the amount used 

 and on the character of the plant treated. Thus, from experiments 

 which I made in 1872, a thorough coating of a mixture of one part of 

 Green to fifteen of flour, while injuring some of the leaves of peas, 

 clover and sassafras, had no injurious effect on young oaks, maples 

 and hickories, or on cabbage and strawberries ; while the fact has long 

 been known that when used too strong and copiously it destroys 

 potato vines. It is for this reason that the experiments made during 

 the past year on beets, by a committee appointed by the Potomac 

 Fruit Grower's Society, are' of little value, as against the universal 

 experience of the farmers of the Mississippi Valley. The mixture 

 used by the committee, and which they call "highly diluted," con- 

 sisted of one part of Green with but six of the dilutent, instead of 

 from twenty-five to thirty parts of the latter ; and it is no wonder that, 

 as reported by the committee, the vitality of the plants was seriously 

 impaired. There can be no question, therefore, about the injurious 

 effect of the Green upon potato vines, when it is used pure or but 

 slightly diluted ; yet in this case, since it is the office of the leaves ta 

 expire rather than inspire, we cannot say that the plant is injured, or 

 killed by absorption, any more than if it were injured or killed by hot 

 water, which, according to the degree to which it is heated, or the 

 copiousness of the application, may either be used with impunity or 

 with fatal effects. Indeed, judging from my own experience, I very 

 much incline to believe that future careful experiments will show that 

 injury to the leaf by the application of this compound, arises more 

 often from the stoppage of the stoma, which is effected as much by 

 the dilutent as by the arsenite itself. So much for the influence of 

 the poison when coming in contact with the plant above ground. The 

 question as to how it affects the plant below ground, through the 

 roots, may be considered in connection with — 



Its Influence on thk Soil. — As Prof. J. W. Johnson, in an admi- 

 rable review of this subject, has recently stated:* "One pound 

 of pure Paris Green contains about ten ounces of white arsenic, 

 and about four ounces of copper;" or, to state it in the usual way, 

 Sweinfurtor jowr-g Paris Green contains fifty-eight per cent, of arsenious 



* New York AVeekly Tribune, December 16, 1874. 



