12 



be subsequently planted in it. This matter has already received 

 some attention, particularly by the Colorado Experiment Sta- 

 tion. There is still some difference of opinion as to the possible 

 harmf ulness of continued spraying with arsenic. Bishop 1 made 

 analyses of potatoes after the vines had been sprayed with Paris 

 green and found that they contained . 0002 per cent of arsenic. 

 Breteau 2 made an examination of wine obtained from grapes 

 picked from vines which had been sprayed with arsenicals and 

 found . 003 to . 2 mg of arsenic per liter of wine. Comere 3 cul- 

 tivated algae in solutions of potasium arsenate. This investiga- 

 tor found that algas not only grew well in nutritive solutions con- 

 taining arsenate but that arsenic acid could replace phosphoric 

 acid in such plants. Hyslop 4 found that in cattle which had been 

 sprayed with arsenical solutions, arsenic was present in urine 

 but not in meat or milk. Collins 5 made cultures with barley in 

 which arsenic was added at the rate of 11 pounds per acre nor- 

 mally. The grain of barley grown in the pots contained arsenic 

 to the extent only of -t oz. per acre and the straw 1% oz. per 

 acre. Arsenic has been found in minute quantities in the fruit 

 and in all parts of fruit trees which have been continuously 

 sprayed with arsenic. It is well known that plants readily ab- 

 sorb arsenic from the soil but a considerable variation exists in 

 their sensitiveness to this chemical. In the long-continued liti- 

 gation between the smelters and cattlemen in Deer Lodge Val- 

 ley, Montana, an excellent opportunity was had of studying the 

 effect of arsenic upon vegetation and live stock. Unfortunately, 

 too little attention was given in this extensive investigation to 

 the effect of arsenic upon plants when absorbed into their tissues. 

 The arsenic in this case was deposited largely upon the surface 

 of the plants in dust which settled from smelter fumes and 

 which contained arson io in large quantities. In all cases, how- 



1 Jour. Am. Chem. Soc. 28 (1906), p. 184. 



2 Jour. Pharm. Chim. 28 (1908), p. 156. 



3 Bui. Soc. Bot. France 56 (1909). p. 147. 

 i Xatal Agr. Jour. 15 (1910), pp. 693-697. 



5 Jour. Soc. Chem. Ind. 21 (1902), pp. 221-222. 



