BY MEANS OF THE PYRETHRUM. 541 



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. 



bisects Destroyed by the Powder. — The principal insects to 

 which the powder is destructive may be ranged under four 

 classes — first, insects injurious to agriculture and horticulture ; 

 second, insects obnoxious to man and his habitation; third, insects 

 destructive to certain substances, as wool, furs, feathers ; and fourth, 

 insects injurious to museums 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, &c, are 

 subject to annoyance from insects which cannot withstand the effects 

 of this powder. Of the numerous insects injurious 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, &c. It is evident that not only the per- 

 fectly 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 exten- 

 sive bakeries, may use the powder with great advantage for the destruc- 

 tion of weevils, midges, crickets, cockroaches, &c, the great plague of 

 those establishments. The powder is equally efficacious in destroying 

 insects which are a constant source of annoyance to the inhabitants of 

 cities and the country. Gnats and musquitoes are banished ; bugs, 

 fleas, and flies disappear from houses under its influence. As to manu- 

 factured articles, the powder is applied 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 larvae will be most 

 effectually destroyed. 



2. Feathers. — The same result will be arrived at by using this powder 

 for the preservation of the costly products of feather dealers. Most 

 woollen products have also a number of insect enemies, especially in 

 their undeveloped state, as larvse. The powder of Pyrethrum, if applied 

 in proper time, will effectually preserve all woollen articles. Natural 

 history, too, has its share of the advantages afforded by this powder in 

 the preservation of collections of mammalia, birds, fishes, reptiles, 

 insects, and anatomical preparations. 



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 



