Insect-powder

Insect-powder is a greenish-yellow powder having a slightly pungent odour. When genuine it is prepared by powdering the closed flowers of various species of Pyrethrum, especially P. carneum, P. roseum, and P. cinerariifolium. When dusted on fleas and other insects it soon stupefies and finally kills them, but whether this is due to subtle emanations from the oil or to the contact with the powder is undetermined. It is generally stated that the volatile oil does not possess this action, but the writer has noticed that when midges alight on a hand which has previously been rubbed with an alcoholic tincture of the powder they become stupefied, and in many instances rapidly die. The powder is innocuous to man, although it is stated to cause partial confusion of ideas in those who sleep in a room in which much of it has been used.