i2 THE GYPSY MOTH APPENDIX. 



in the use of arsenate of lead is an entirely harmless one. 

 The odor of the spray when very pronounced often causes 

 considerable anxiety among- those engaged in spraying, and 

 in one or two cases has been known to produce nausea. 

 This odor is not produced by the arsenic or the lead, but is 

 the rich creosote smell remaining in the crude acetic acid 

 used in the manufacture of acetate of lead. This acid is one 

 of the resultants of the destructive distillation of wood, and 

 retains the smoky odor even after passing through several 

 chemical reactions. 



It may be stated, in general terms, that w r hile an occa- 

 sional person may become poisoned during extensive spray- 

 ing operations with arsenate of lead, premonitory symptoms 

 appear in ample time for a change of work to be arranged ; 

 and since the conditions existing in the work against the 



O O 



gypsy moth are exceptional, the farmer or fruit grower may 

 use this insecticide with less fear of danger from poisoning 

 than is the case where Paris green or London purple is used. 

 In all cases proper care must be taken in handling the poison 

 and in preventing the exposure of the skin to the spray. 



The danger to animals from feeding on grass under trees 

 that have been sprayed is a matter that has at times received 

 a large measure of popular attention in the region infested 

 by the gypsy moth, and at the time of spraying we have 

 always taken the precaution to advise all property owners of 

 the possible danger to their fowls and live stock. The ex- 

 periment detailed below is of interest in this connection. 



On June 26, 1896, sufficient grass to make two large feed- 

 er 53 



ings for a horse was cut and spread beneath a pear tree of 

 medium size, and the tree heavily sprayed with arsenate of 

 lead, at the rate of 20 pounds to 150 gallons of water. The 

 drippings from the tree were not sufficient to discolor the 

 grass to any marked degree, so the nozzle was turned on 

 to the grass, and the latter thoroughly drenched. By a 

 previous arrangement with Miiller Brothers, tannery pro- 

 prietors, North Cambridge, a horse had been secured for 

 experimental purposes. This horse weighed about 1,200 

 or 1,300 pounds, was perfectly sound except for a badly 

 sprained leg, and because of this latter defect was soon to be 

 slaughtered. The grass treated as described was taken to 



