AN AGRICULTURAL REVOLUTION. 647 



commonly in use, is done with proper reference to the time, 

 methods, and conditions of treatment, there is no danger to the 

 consumer. Both practical experience and chemical tests have re- 

 peatedly shown that apples sprayed early in the season with Paris 

 green or London purple retain none of the poison at the time of 

 ripening. The most recent demonstration of this appears in the 

 last report of the experimental farms of Canada. A peck of 

 Rhode Island greening apples that had been sprayed twice with 

 Paris green (one pound to two hundred gallons of water) were 

 carefully gathered, without rubbing, and tested for arsenic. "The 

 process to which they were submitted is one that affords extremely 

 accurate results, and is considered the most delicate of all for the 

 detection of arsenic. It is capable of revealing the presence of 

 one fifty-thousandth part of a grain of arsenic. If twenty-three 

 thousand bushels of apples contained two and a half grains of 

 arsenic, the minimum fatal dose for an adult, the poison could 

 have been detected by this method." Notwithstanding the most 

 careful analysis no traces of poison were found ; and, in conclusion, 

 the chemist states : " I am of the opinion that further experiments 

 of this nature would only serve to corroborate this negative result, 

 and to prove that there are no grounds on which to base a sus- 

 picion that our sprayed apples are poisonous. The insoluble 

 character of this poison precluding its assimilation by the apple, 

 if such were possible, the infinitesimal part of Paris green that 

 can remain on the apple, the frequent rains subsequent to the 

 spraying, ... all go to substantiate the argument that there is 

 not the slightest danger of poisoning in using sprayed apples." 



There is abundant evidence of a similar nature concerning the 

 use of copper salts on grapes. In France, where a large proportion 

 of the grape crop is converted into wine, elaborate investigations 

 have shown that practically none of the copper salts are present 

 in wine from sprayed vineyards. Prof. B. Fallot, of the School 

 of Agriculture at Montpellier, in recording the results of one of 

 these investigations, says: "The figures obtained have proved 

 once more that wines, after the grapes have received numerous 

 treatments with large quantities of salts of copper, contain scarcel} 1 " 

 a trace of this substance, and are entirely harmless." 



Such is a meager and imperfect outline of this most recent 

 improvement in the art of agriculture, which I have ventured to 

 call an agricultural revolution. This improvement has been 

 brought about by the combined efforts of the entomologist, the 

 botanist, the chemist, the mechanician, and the agriculturist. 

 Every step forward has been the result of careful study and ex- 

 periment, and the whole subject is a striking illustration of the 

 practical benefit agriculture may derive from scientific investiga- 

 tion and systematic experimentation. 



