INSECT POWDER. 67 
vulsive movements. The resin when dusted on insects acted very 
energetically. Solutions of the powder made with water or with 
dilute alcohol were found to be entirely inactive. 
Dal Sie (60), in 1879, claimed to have proven the presence of a free, 
easily volatilized acid which was found in the ethereal, alcoholic, or 
aqueous extracts of the powder. From the ether extract of the flowers 
he obtained not only a crystallizable acid, but also an aromatic 
smelling acid of oily consistency at ordinary temperature. From 
the alcoholic extract he obtained a resinous matter resembling a 
glucoside, probably the same as that found by Pother, since under 
the influence of dilute sulphuric acid it split up into sugar and another 
product. According to Dal Sie, since the fumes which result from 
the incomplete combustion of insect powder exhibit the toxicity 
of the original powder, the toxic principle must be volatile without 
decomposition, and the free volatile acid is, therefore, the most 
active constituent of Pyrethrum. 
Oscar Tex tor (272), 1881, as the result of his tests, stated that 
"the active principle of Persian insect powder is, in nature, a soft 
resin." He pulverized (80-mesh) 1| ounces of whole flowers (species 
not indicated), and percolated the powder with benzine for 6 hours, 
using 6 fluid ounces. The benzine solution was evaporated, water 
added, and again evaporated to remove any volatile oil. The residue 
was treated with dilute acid and filtered. No alkaloid could be de- 
tected in the filtrate by phosphomolybdic acid, Mayer's reagent, or by 
a solution of iodin in potassium iodid. The benzine extract, the 
benzine extract in alcohol precipitated by acid, and the benzine 
extract in caustic potash and precipitated by acid, were all poisonous 
to flies. The benzine extract in alcohol was acid to litmus. A test 
for essential oil was made by allowing the powder to stand in dilute 
salt solution for 24 hours and then distilling, but none was obtained. 
Hirschsohn (133), in 1890, found that alcohol, ether, chloroform, 
or benzine would dissolve the active principle of insect powder. 
The extract obtained with these solvents, when added to an inactive 
powder, e. g., powdered chamomile, produced a powder as active 
as the original insect powder before extraction. From the work 
of Hirschsohn, the active principle would appear to be nonvolatile, 
as he found samples of powder which had stood for 5 years in paper 
boxes still as active as fresh powder. Heated at 120°, insect powder 
lost its odor, but was as active as ever against flies. To see if the 
active principle was acid in nature, he treated powder with alcoholic 
ammonia, also with alcoholic potash, but after drying in the air the 
powder was as active as ever. Placed for 24 hours in water, the water 
became acid, but the powder after drying was still active. 
