PREVENTIVE MEASURES 
197 
icals used to destroy the larvae in the manure pile may 
be roughly divided into two classes: (i) Contact poi¬ 
sons, and (2) stomach poisons. To the first class be¬ 
long such preparations as the kerosenes (generally 
used in the form of emulsions) and the creosol prepa¬ 
rations, also chloride of lime. To the second class be¬ 
long the arsenicals, represented by arsenate of lead and 
Paris green. All of these insecticides are more or less 
effective when used in proper concentrations and in 
sufficient quantities, but none of them can be applied 
with any degree of safety to man or to the domesticated 
animals because of either their inflammable, poisonous, 
or corrosive nature.” 
Prof. S. A. Forbes, of Illinois, also caused a series 
of experiments of this sort to be carried on at the Illi¬ 
nois State Experiment Station at Urbana. The work 
was done under his direction by Mr. J. J. Davis. The 
notes have not been published, but have been kindly 
sent to the writer by Professor Forbes. In these ex¬ 
periments it was found that three pounds of hydrated 
high calcium lime of the Marblehead Lime Company, 
mixed with fifteen pounds of horse manure, killed 
ninety-four per cent, of the larvae; two pounds mixed 
with twelve pounds of manure killed sixty-nine and 
one-tenth per cent, of the larvae; four pounds with 
twelve pounds of manure killed sixty-one and three- 
tenths per cent. The diminished percentage in the 
last two experiments is accounted for by the fact that 
the larvae were nearly full-grown. 
An experiment with two pounds of iron sulphate 
