8 
arsenious oxide can not be employed on account of its scalding action 
on the foliage, and in the case of any of the arsenicals the percentage 
of soluble arsenic (arsenious oxide) should be at the very minimum, 
certainly not in excess of 3 or 4 per cent. With more than 4 per cent 
soluble arsenic there is great danger of scalding the foliage, the 
danger increasing with the percentage of soluble arsenic.¢ 
Paris green.—Paris green is a definite chemical compound of white 
arsenic, copper oxide, and acetic acid, and is known as the aceto- 
arsenite of copper. Properly compounded and washed, it should be 
substantially uniform in composition and nearly free from uncom- 
bined soluble white arsenic. It is a rather coarse powder, or, more 
properly speaking, crystal, and settles rapidly in water, which is its 
greatest fault. To give better suspension in water, it should be re- 
duced to such fineness by grinding that it will pass through a 100-mesh 
sieve. Its high cost (varying from 20 to 40 cents a pound, following 
the market price of copper and arsenic) is further increased by its 
being crystallized with acetic acid, making it a more brilliant pigment, 
but giving it a coarse grain and rendering it a poorer insecticide. The 
standards of purity demanded by various States have led most manu- 
facturers to produce a very fair article, but if there is any doubt of 
purity a sample should be submitted to the State Experiment Station 
or to the United States Department of Agriculture for analysis. 
Copper arsenite—Copper arsenite, often called Scheele’s green, is 
the simple arsenite of copper, differing from Paris green in lacking 
acetic acid. It is a much finer powder than Paris green and therefore 
is more easily kept in suspension, and it costs considerably less per 
pound. It is dull in color, lacking the brilliancy of Paris green. 
When properly prepared and washed by the manufacturers, it is no 
more harmful to the foliage than Paris green when the latter is 
brought to an equal fineness, and should supplant the latter as an 
insecticide. It is used in the same way and at about the same strength 
as Paris green. 
® Hellebore.—The powdered roots of the white hellebore (Veratrum viride) 
are often recommended and used as an insecticide, particularly as a substitute 
for the arsenites. This substance is useful when a few plants only are to be 
sprayed, as in yards and smal! gardens, but is too expensive for large opera- 
tions. It kills insects in the same way as the arsenicals, as an internal poison, 
and is less dangerous to man and the higher animals; but if a sufficient amount 
be taken it will cause death. It is particularly effective against the larve of 
sawflies, such as the cherry slug, rose slug, currant worms, and strawberry 
worms. 
It may be applied as a dry powder, preferably diluted with from 5 to 10 parts 
of flour, and dusted on the plants through a muslin bag or with powder bellows. 
The application should be made in the morning, when the plants are moist with 
dew. Used as a wet application, it should be mixed with water in the propor- 
tion of 1 ounce to the gallon of water and applied as a spray. 
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