June, 1917.] ARSENICAL RESIDUES AFTER SPRAYING. 5 



PAGE 



found per apple in fruit from sprayed trees, picked 

 before any rain, continuing the feeding with multiples 

 of this unit 29 



Daily doses of lead arsenate, beginning with 1, 2 or 3 units 

 and increasing to 8 units for 30 days did not produce 

 fatal poisoning. Daily doses of 6 units, fed for 30 

 days without previous smaller doses, did not produce 

 fatal poisoning 31 



When white arsenic was substituted for arsenate of lead, 

 fatal results began with daily doses of 4 units adminis- 

 tered thru 14 days 31 



The evidence summarized indicates that under ordinary 

 conditions no apples will reach the consumer carrying 

 such amounts of lead arsenate per fruit that a healthy 

 human adult can eat enough at one time to cause fatal 

 poisoning. Strawberries that are fulty formed should 

 not be directly sprayed with lead arsenate, unless they 

 are to be scrubbed before using. Blackberries should 

 not be directly sprayed after the berries are formed. 

 Currants, if so sprayed, should be washed. With cab- 

 bages and lettuce ready for market arsenate of lead 

 should not be apphed except sparingly and in that event 

 the outer leaves should be removed and the heads 

 should be washed. The case is not clear as to possible 

 injurious effects from long-continued daily consump- 

 tion of fruits carrying relatively small residues; but it 

 is believed that the use of apples from trees sprayed 

 with lead arsenate, at the rate of 3 lbs. of the paste to 

 50 gallons of water, offers very slight danger, if any, 

 this danger being negligible in the case of winter fruit 

 sprayed two months or more prior to harvest. Early 

 fruit sprayed just before harvest should be wiped 35 



Experiments with Live Stock 37 



Drip from Trees 37 



Experiments show an average drip from trees amounting to 

 11.2 per cent where spray material was applied with 

 reasonable care 37 



