INSECT POWDER. 67 



viilsivo 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 foimd 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 Rother, since under 

 the influence of dilute sxdphuric 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 P3rrethrum. 



Oscar Textor (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) IJ 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 i^owder with alcoholic 

 ammonia, also with alcoholic potash,, but after dr3^ing 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. 



