INSECT POWDER. 71 



in the direct sunlight, a white wax, of melting point 56.5°, was ob- 

 tained. After separation of the waxy bodies from the solution a 

 sugar (dextrose) was shown to be present. Altogether, Thoms 

 succeeded in isolating from insect powder: (1) An essential oil, (2) 

 a volatile acid, (3) a wax, (4) a nonvolatile, potassium permanganate 

 reducing, balsamlike acid, (5) chlorophyll, (6) colophonic acid, (7) 

 tannic acid, (8) a body with alkaloidal properties, (9) a body with 

 glucosidal properties, and (10) sugar. Thoms found the petroleum- 

 ether extract and the essential oil to possess toxic properties, while 

 the nonvolatile acid, the glucoside, and the other substances were 

 harmless to insects. 



De Boisse (64), 1895, claimed that the active principle of Pyre- 

 thrum cinerarisefolium is a yellow resin soluble in sulphuric ether, 

 insoluble in water, very slightly soluble in alcohol, carbon disulphid, 

 and fatty bodies. Alkalis decompose it rapidly. The flowering 

 heads and leaves contain a good deal of this resin ; the lower parts of 

 the stems, very little. De Boisse gives no experimental proof for 

 these statements. 



Durrant (73), in 1897, stated: "The toxic properties of insect pow- 

 der are due to (1) a volatile oil amounting to 0.5 per cent in picked 

 specimens of closed flowers and much less in open flowers ; (2) a soft 

 acid resinous body which is the principal source of the toxic effect. 

 It is found to the amount of 4.8 per cent in selected closed flowers, 

 less than 4 per cent in half-open flowers, and still less in flowers that 

 are fully open ; the whole plant apart from the flowers contains mere 

 traces of resin." 



Gerard (93), 1898, stated that the active principle of Pyrethrum 

 consists of two different substances: (1) An oleo-resin, and (2) an 

 essential oil. These are found principally in the bracts and around 

 the ovaries of the flowers, comparatively little being found in the 

 corollas. 



Sato (236, 237), as a result of work done in 1905-1907, reports the 

 isolation of a light-yellow, odorless, transparent, sirupy resin from 

 Pyrethrum flowers, which he calls pyretol. At first this is tasteless, 

 but later has a benumbing effect. It is insoluble in water and dilute 

 acids, and soluble in alcohol, ether, and petroleum ether. It is 

 soluble in hot alkaline solutions, but when precipitated from such 

 solutions by acids the resm becomes completely inactive. 



Fujitani (89), in 1909, conducted an elaborate research on the flow- 

 ers of CJirysantJiemwrn cinerarisefolium, using flowers cultivated in 

 the Provinces of Ki-i and Mikawa, Japan. The flowers were ground 

 and the powder soaked for 1 week in 95 per cent alcohol at room 

 temperature. The alcohol was distilled off, leaving an extract of a 

 greenish-brown color and a characteristic odor of insect powder, and 

 quite toxic to insects. The yield was about 10 per cent. The alcohol 



