June, 1917.] ARSENICAL RESIDUES AFTER SPRAYING. 55 



material carrying arsenic and for 31 days had been in apparently 

 normal condition. 



In 9 days the sheep consumed all the grass beneath the sprayed 

 tree. It was then moved to a stock pen. It exhibited no symp- 

 toms of poisoning. 



A pen was now set up beneath another tree of medium size 

 and this tree was sprayed with arsenate of lead, at the rate of 6 

 lbs. of the paste to 50 gallons of water. The material here was 

 applied in excessive amounts, so that there was a good deal of 

 drip. 



Two sheep were placed in the pen. These sheep had been 

 pastured on sprayed grass earlier in the season, but had not had 

 access to material carrying arsenic for 29 days and for 24 daj^s 

 had apparently been in normal condition. Two days after the 

 experiment was started there was a heavy rain. Therefore, 

 another tree was sprayed as before and the sheep were removed 

 to the grass beneath it. On the second day in the new plot one 

 of the sheep e;xhibited slight symptoms, but in another two 

 days these symptoms had disappeared and both sheep seemed 

 quite normal. At the end of 5 days they had eaten all of the 

 grass in the plot and were now moved to the stock pen, free 

 from spray material. Here they were kept under observation, 

 but developed no further symptoms. 



Another pen was set up beneath a tree, which was then sprayed, 

 using a coarse nozzle and applying 12 gallons of material, at the 

 strength of 3 lbs. of arsenate of lead paste to 50 gallons. 



Two sheep were pastured in this pen. In 7 days they had eaten 

 all of the grass in the plot. During this time they showed no 

 symptoms of poisoning and to the end of the period they 

 seemed entirely normal. 



Another pen was set up and the tree within it was heavily 

 sprayed with a coarse nozzle, using arsenate of lead at the rate 

 of 6 lbs. of the paste to 50 gallons of water. Twelve gallons of 

 material were applied. Two sheep were placed in this pen. On 

 the first day there were slight symptoms of poisoning and this 

 became somewhat more pronounced on the second day. But on 

 the third day the symptoms had largely abated, appetite had 

 come back and at the end of the fifth day the sheep appeared 

 normal. 



In a final lot the tree was sprayed heavily with a coarse nozzle^ 



