INSECTS AND INSECTICIDES 
29 
with other substances. Because some states have passed laws re¬ 
quiring a high percentage of arsenic in Paris green, arsenic has 
been used as an adulterant of this poison, and thereby working an 
injury to the purchaser if not a benefit to the manufacturer of it, 
because arsenic is much cheaper than Paris green; and when it is 
mixed with the latter, it greatly increases its liability to burn 
foliage. The reason that white arsenic burns foliage badly is it 
dissolves in water and, when in solution, it penetrates the leaves 
and kills the living tissue. Arsenical mixtures must never be in 
solution , but only in suspension , in the water that is used to dis¬ 
tribute them upon foliage. 
2. ARSENIC BRAN-MASH. 
Prepared by mixing one pound of arsenic and 20 to 50 pounds 
of bran together with just water enough to thoroughly moisten the 
mass. Some prefer to add a pound of sugar to the above in order 
to cause the particles of bran to adhere to each other, so that it may 
be distributed in little balls pressed together with the hands or 
with a paddle. This poisoned bran is used for the destruction of 
grasshoppers in orchards and vineyards where it is not possible to 
use a hopper-pan. Many prefer to sow the moistened bran and ar¬ 
senic broadcast where the grasshoppers are numerous. Paris 
green may be substituted for the arsenic. 
3. PARIS GREEN. 
This poison in a pure state is said to be composed of three sub¬ 
stances—arsenious acid, acetic acid, and copper oxide—united in 
a chemical combination. The percentage of arsenic may vary 
considerably, as these substances do not always combine in exactly 
the same proportions. The range is nearly always between 55 and 
60 per cent, arsenic, with an average of about 58 per cent. *Mr. J. K. 
Haywood, one of the chemists in the Department of Agriculture 
at Washington, D. C., says that the chemical composition of Paris 
green should be: 
Per cent. 
Arsenious acid.58.65 
Copper oxide.31.29 
Acetic acid .10.06 
Pure Paris green is one of the very best of the arsenical com¬ 
pounds for the destruction of insects, but this poison is often found 
greatly adulterated upon the market. If adulteration is sus¬ 
pected, or if the poison is being purchased in any considerable 
quantity, it is advisable to test its purity in some way. Pure Paris 
*Farmer’s Bull. No. 146, U. S. Dept, of Agr. 
