PARIS-GREEN. 
73 
(The ordinary application to a Potato-field is from a pound to two 
pounds per acre.) 
“2. Arsenic cannot be absorbed and assimilated by the plant in 
the economy of growth. All of the plants grown in the arsenical soil 
tried by Marsh’s test failed to indicate the presence of arsenic. 
“3. Potatoes subjected to applications of Paris-green failed to give 
evidence of the presence of arsenic”; and after giving notes of many 
kinds of insects to which this insecticide may be applied with especial 
benefit, and detailed observations of its success in clearing spring 
Looper Caterpillar, Dr. Lintner concludes his exhaustive paper on 
Paris-green, its nature, use, and method of application, with these 
words:— 
“ In brief, it will be of service, whenever extensive depredations 
occur, not easily controllable by other means, from leaf-eating insects 
and their larvse, upon leaves not used for food of men or animals, or 
only used after so long a period that the poison shall have been 
entirely washed away, or even upon edible fruit, occurring at the time 
in so immature a stage or in such condition that it will not permanently 
retain the poison.”* 
The above observations are not offered as in any way giving a full 
account of the application of Paris-green, but simply as notes of what 
it has been found may be done in the case of Looper Caterpillar to 
check this destructive attack. For full accounts of everything that 
can be thought of with regard to all methods of application to most 
kinds of crop, the reader is referred especially to the publications of 
the U.S.A. Department of Agriculture, some of which have been 
quoted ; also Beports of the Official Entomologists of different States, 
especially Dr. Lintner’s Beport, quoted above ; and also the official 
notices, likewise quoted, of the Entomologist to the Dominion of 
Canada. 
At first here, as elsewhere, some difficulties in application are likely 
to occur; if too strong, or the mixture not evenly distributed, the 
leafage will be, if too weak, the caterpillar will not be, hurt; but the 
great point in first experiment is to be sure that the mixture is 
not too strong. If too weak, this mistake is easily corrected, and it 
would be best to try a pailful at first on a tree or two than to risk more. 
Also it is advised that it should be used in dry weather, or necessarily 
the application may be washed away; and likewise it is to be remem¬ 
bered that Paris-green is insoluble ; it does not dissolve in water, but 
mixes with it, so unless the mixture is kept stirred, or by some means 
or other in movement, the powder will settle down at the bottom of 
the water. 
* “Paris*green as an Insecticide,” pp. 25—34 of Dr. Lintner’s ‘ First Annual 
Report as State Entomologist of New York State, U.S.A.,’ quoted above. 
