ON DESTRUCTION OP INSECTS BY PYRETHRUM. 
175 
receptacles for holding the powder seem to he bottles ; these, if well corked, will keep out 
moisture, which is so injurious to the properties of the powder. If the powder is not to 
be kept long, small boxes will do as well as bottles. 
Insects destroyed by the Powder. —The principal insects to which the powder is de¬ 
structive may be ranged under four classes :—first, insects injurious to agriculture and 
horticulture ; second, insects obnoxious to man and his habitation ; third, insects destruc¬ 
tive to certain substances, as wool, furs, feathers; and, fourth, insects injurious to mu¬ 
seums of animal and vegetable products, and collections of natural history. We do not 
pretend to enumerate all the insects to which the powder is destructive ; it will suffice to 
mention a few instances, which will sufficiently show what applications may be made of 
it. Our domestic animals,—dogs, cats, fowls, pigeons, etc.,—are subject to annoyance from 
insects which cannot withstand the effects of this powder. Of the numerous insects in¬ 
jurious to agriculture and horticulture we may mention the following which have been 
destroyed by it:—the weevil, bark-beetle, wheat-fly, maggots, cocci, aphides, earwigs, 
spiders, ants, etc. It is evident that not only the perfectly developed insects are destroyed, 
but also the larvae, which in some cases do greater injury than the insects themselves. Large 
depots where military stores or navy supplies are kept, and especially extensive bakeries, 
may use the powder with great advantage for the destruction of weevils, midges, crickets, 
cockroaches, etc., the great plague of those establishments. The powder is equally effica¬ 
cious in destroying insects which are a constant source of annoyance to the inhabitants 
■ of cities and the country. Gnats and mosquitoes are banished; bugs, fleas, and flies dis¬ 
appear from houses under its influence. As to manufactured articles, the powder is ap¬ 
plied effectually to the following :— 
1. Furs.—These require great care for their preservation. Numerous insects live upon 
them. Their propagation is rapid. The only remedy against their ravages hitherto has 
been pepper or camphor, but by using the powder of Pyrethrum the insects and their 
larvoe will be most effectually destroyed. 
2. Feathers.—The same result will be arrived at by using this powder for the preserva¬ 
tion of the costly products of feather dealers. Most woollen products have also a num¬ 
ber of insect enemies, especially in their undeveloped state, as larvae. The powder of 
Pyrethrum, if applied in proper time, will effectually preserve all woollen articles. Na¬ 
tural history, too, has its share of the advantages afforded by this powder in the preser¬ 
vation of collections of mammalia, birds, fishes, reptiles, insects, and anatomical pre¬ 
parations. 
Herbariums are very frequently devastated by insects gradually piercing the paper as 
well as the dried plants, reducing the latter almost to powder, more especially if they 
have not been poisoned by chloride of mercury dissolved in alcohol—a substance both 
expensive and dangerous. By applying a pinch of the powder between the leaves of his 
herbarium, the botanist will soon get rid of the enemies of his collection. Finally, a 
most important advantage of this powder is that it is innocuous to man, and can be ab¬ 
sorbed by the human subject without the slightest danger to his health. Some physi¬ 
cians of celebrity even assert that the powder can be advantageously sprinkled upon sores 
or open wounds that diffuse an unpleasant odour. 
Mode of applying the Powder. —In using the powder it must be applied carefully and 
in sufficient quantity, otherwise the result will be unsatisfactory, especially if used 
against some of the hardy or very resisting species of insects. Occasionally the powder, 
by being exposed to the air or moisture, will have lost its destructive properties, so as to 
render the result doubtful and wholly inefficient; at others the result has been unsatis¬ 
factory, because the most favourable moment for the operation has been overlooked. A 
rainy or wet day, for instance, always lessens the destructive efficacy, because the powder, 
containing a very volatile essential oil, renders the conservation of this principle ex¬ 
tremely difficult. 
Of all the methods for applying the powder to plants attacked by insects, including 
the vine, the bellows will best accomplish the object. As there is only a small quantity 
of powder thrown at once, the loss will be very small, whilst in any other way a good 
deal of it will fall upon the ground. The powder should be directly applied to the parts 
operated on, and with care and precaution it may be made to penetrate into the most in¬ 
accessible parts of a plant. If, for instance, a plant has been attacked by plant lice, 
which are often hidden or masked by thick foliage, it will become necessary to turn aside 
this foliage, so as to have the insects exposed, and the powder directly brought into r / l 
tact with them. o 2 
