ARSENIC FOR DESTROYING COTTON WORMS. 147 
use of them by planters. The letter of the law too often negatives the 
spirit of the law, and it seems that the Patent Office has been forced to 
issue the patents above alluded to on the ground and decision that any 
change in the compounds of a mixture makes of it, in law. a new sab- 
stance. 
ARSENIC. 
While commercial arsenic, salts of arsenic, and their various com- 
pounds are much cheaper than Paris green, yet this advautage is 
more than counterbalanced by the injurious property they possess, in 
a more or less marked degree, of scalding the leaves and causing the 
squares and young bolls to shed. Moreover, on account of their white 
color, there is more danger of injury to man and animals in their use 
than in that of colored preparations, which are less likely to be mis- 
taken for harmless substances. Great care and precaution ate, there- 
fore, necessary in applying these arsenic poisons. When applied in 
just the right proportions to kill the worms without injuring the cotton 
they are valuable substitutes for the more expensive Paris green, bat 
unfortunately these proportions vary with each pari ieular combination, 
the condition of the plants, temperature, and weather, and time of ap- 
plication, so that they can be satisfactorily ascertained only by abso- 
lute experiment. 
It is for this reason that the Paris green mixtures have held their 
own against the cheaper compounds, and most planters, even where 
these last are used, fiud it desirable to still mix a certain proportion of 
the green n itb them. 
The cheapness of the arsenic, combined with the fact that under ver\ 
favorable circumstances it is not uncommonly applied with success, will 
give to it a conspicuous place among the remedies for the Cotton Worm, 
so long as mineral poisons are not superseded by others. The high 
price asked for some of the patented compounds is entirely unwarranted, 
as their value in every case depends on the arsenic. 
Commercial arsenic, costing from 7 to 10 cents per pound, is applied 
in powder form at the ratio of A pound to from 18 to 25 of any of the 
ingredients used with Paris green. Used in water, these arsenic coin 
pounds give less satisfaction because of the dangers to the plant already 
alluded to, which are then increased. Counting 40 gallons ol liquid for 
one acre of cotton, the arsenic used should not exceed 1 pound to 200 
gallons of water : and this mixture must be very evenly distributed, as 
even a slight overdose will scorch the Leaves. It is an interesting fact 
that already in 1871 a patent was obtained for the use of arsenic against 
the Cotton Worm by Mr. Thomas W. Mitchell, of Eichmond, Tex. (No. 
110774, January 3, 1871 ; reissue No. 5935, June 30, 1874: 92 grains of 
opaque arsenic, or 293 grains of transparent arsenic to one pint of 
water). 
Arseniate of soda. — This has the advantage of being perfectly sol- 
