138 REPORT 4, UNITED STATES ENTOMOLOGICAL COMMISSION. 
Finally, too muck stress cannot be laid on the importance of having 
the materials ready, prepared in advance, or on their use as soon as the 
eggs or young worms are noticed. It is too often the habit to wait until 
the plants begin to be u ragged" before attempting to poison. The 
operation is always more costly and unsatisfactory at this period, and 
there is danger that, with the most strenuous efforts, irreparable dam- 
age will be done before all the cotton is gone over. It often happens, 
also, since the same influences cause the multiplication of the worms 
over pretty large areas, that a sudden and general demand for the poi- 
sons by those who Lave not previously laid in a stock increases the price 
or exhausts the market, so that many are left without hope of saving 
their crop. 
ARSEXICAL COMPOUNDS. 
Arsenical compounds have the acknowledged disadvantage of being 
dangerous to man and beast. Some writers, taking a most narrow and 
theoretical view of the subject, bitterly object to their use on the score 
of their dangerous character, exaggerating in their enthusiasm the in- 
jury that has resulted from their use. Not only hundreds of tons, but 
thousands of tons of these mineral poisons have been employed during 
the past decade by farmers throughout the country, whether to protect 
the potato crop, or the cotton crop, or other products of the soil from 
the ruinous attacks of insects. The general experience during this long 
period and over the whole country is so emphatically in favor of their 
use and their perfect safety and harmlessness, with ordinary precau- 
tions, as to render almost laughable the objections of the few persons 
referred to. No advancement, no improvement, no general benefit to 
the human race is ever accomplished without some attendant danger, 
and those who inveigh against such improvements as increasing the 
risks to life stand on the same footing as the opponents to arsenical 
poisons as insecticides. It is a noteworthy fact that, since we have been 
pursuing this cotton insect investigation, not a single fatal case of 
human poisoning by the use of these minerals against the worm has 
come to our notice from the South, notwithstanding tbey are often used 
in that section of the country with great recklessness. Nevertheless, 
it is no uncommon thing to hear of partial poisoning among negroes, 
resulting from that indifference which comes from constant use, and the 
importance of care and caution cannot be too strongly urged, especially 
near towns or in thickly settled neighborhoods. 45 
None of the correspondents of the Commission report serious injury 
to man by arsenical poison in its application for the Cotton Worm, 
and only one of them reports directly a case of poisoning a horse ; all 
others report such cases from hearsay. 
It has been our principal ambition to discover some substitute for 
these poisons that shall be equally effectual, harmless to man, and 
cheaper. The experiments that have been carried on by the Commis- 
sion with this object have been sufficiently encouraging, as the sequence 
