INSECT POWDER 59 
reasonable to suppose that those examined are fairly representative. 
It is evident that a great many of the insect powders on the market 
have not been made from the flowers as imported and that adultera- 
- tion is being extensively practiced. 
ACTIVE PRINCIPLE OF INSECT POWDER 
PREVIOUS INVESTIGATIONS 
The earliest recorded investigation on the active insecticidal con- 
stituents of insect powder is that of Ragazzini (67), who used the 
powder from C. cinerarizfoluum and concluded that its narcotic 
action was due not to any one substance but to a mixture of sub- 
stances. 
In 18638, Heller and Kletzinsky (1/14) were reported to have found 
that genuine Persian insect powder contained no narcotic or alka- 
Joidal plant poisons or poisonous mineral substances, but only 
ethereal oil and santonin, as the active insecticidal constituents. 
Hanamann (1/4) concluded that Pyrethrum flowers contain no 
poisonous alkaloid or santonin, but mostly indifferent substances, 
and that only the ethereal oil in concentrated form can be harmful. 
He stated that genuine insect powder can have no harmful action on 
the human organism. 
Rother (2354), in 1876, recorded the results of tests on Pyrethrum, 
but did not indicate the species used. He proved the absence of 
alkaloids and stated that the active principle is a glucoside (persicin), 
which can be split up into glucose and an inert body (persiretin). 
He also isolated a yellowish, bitter resin (persicein). Later, Rother 
(235) stated that persicin is not a glucoside and that the glucose 
reaction is due to glucose or a gum preexisting in the powder. 
Jousset de Bellesme (62), in 1876, stated that the toxic principle of 
insect powder is entirely extracted by alcohol. He isolated the 
essential oil of Pyrethrum, and proved its harmlessness on insects. 
Submitting Pyrethrum to the treatment for extracting an alkaloid 
gave a crystallized principle ‘‘which enjoyed to a high degree the 
toxic properties of the plant.” His statements are not accom- 
panied by experimental proof. 
Semenoff (253), in 1877, obtained flowers of Pyrethrum, presum- 
ably P. roseum or carnewm, from Caucasia. Dried at 25° C., the 
flowers were as active against insects as commercial insect powder. 
An essential oil obtained by steam distillation proved to be inactive. 
Distillation in an alkaline solution gave a very small quantity of an 
alkaloid. By macerating 1 pound of the flowers with 5 pounds of 
ether for five days and evaporating the extract, a mixture of resin, 
oil, wax, and acids was obtained. On steam distillation it yielded 
an ethereal! oil that killed insects. ‘2 ine 
Hager (//1), in 1878, reported that the insecticidal activity of the 
flowers of P. carneum and roseum was due to two substances. One 
was a body similar to trimethylamin, which was found in the 
: flowers combined with an acid; the other was a resin found in the 
pollen grains. Hager obtained some of the first substance in combi- 
nation with hydrochloric acid, added to it some potassium hydroxid 
‘solution, and noticed that flies held over the mixture exhibited con- 
‘vulsive movements. ‘The resin when dusted on insects acted very 
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