234 The Spraying of Plants. 



It was all eaten up in an hour or two, and the horse showed no 

 signs of injury. This mixture, remember, was of double the 

 proper strength, was applied very thoroughly, and all the grass 

 fed to and eaten by the horse. This experiment was repeated 

 with the same result. I next secured three sheep. These were 

 kept till hungry, then put into a pen about a tree under which 

 was rich, juicy, June grass and clover. The sheep soon ate the 

 grass, yet showed no signs of any injury. This experiment was 

 repeated twice with the same result. It seems to me that these 

 experiments are crucial, and settle the matter fully. The analy- 

 ses show that there is 110 danger, the experiments confirm the 

 conclusion. 



" Thus we have it demonstrated that the arsenites are effec- 

 tive against the codlin-moth, that in their use there is no danger 

 of poisoning the fruit, and when used properly no danger to the 

 foliage nor to stock that may be pastured in the orchard." 1 



The danger following the use of copper compounds on foliage 

 is naturally even less than when a form of arsenic is applied. 

 One case is on record in which poisoning has followed when 

 grape foliage was eaten by sheep, this having been sprayed 

 with the Bordeaux mixture. 2 Since sprayed foliage is probably 

 never fed regularly to stock, there need be no cause of appre- 

 hension in this respect. 



The extent to which copper is absorbed by foliage still 

 remains an open question. The researches of Millardet and 

 Gayon show that a certain amount of copper is absorbed and 

 retained by the cuticle of the leaf. 3 The investigations of 

 Rumm, however, show that such is not the case. 4 If the 

 copper is actually absorbed the quantities are exceedingly 

 minute. That it possesses a stimulating action upon foliage 

 is also doubtful. Lime may have such an effect, since several 

 cases are on record in which the application of Bordeaux mix- 

 ture produced a greener appearance of the healthy foliage. 



1 A. J. Cook, Ann. Rept. Mich. Bd. Agric. 1889, 320. 



2 Wiener Landw. Ztg. 1892, 494. 



3 Jour. &Ag. Prat. 1887, Jan. 27, 123, and Feb. 3, 156. 



* "Ueber die Wirkung der Kupferpraparate bei Bekampfung der sogenannten 

 Blattfallkrankheit der Weinrebe." Ber. d. Deut. Bot. Ges. Bd. 11, Heft 2, 1893, 

 79-S3; Ibid. Heft 7, 445-152. See, also, adverse critical review by Zimmerman n 

 in Bot. CentralU. 1893, No. 23, 308 ; Nos. 29, 30, 119, 120 ; and Aderhold in Bot. 

 Zeit. No. 11, 1893, 162. Cited by Fairchild in Bull. 6, Sec. Veg. Path. U. S. Dept. 

 Agric. 27. 



