74 



BULLETIN 824, IT. S. DEPAETMEWT OF AGEICULTUKE. 



Table 45. — Summary of investigations on active insecticidal principle of Pyrethrum- 



Continued. 



Year. 



Investigator. 



Bibliog- 

 raphy 

 reference. 



Species of Pyrethrum 

 used. 



Active principle considered 

 to be— 



1879 



DalSie 



60 

 272 

 96 



/ 296, 297, 

 \ 298,299 



133 



77 

 245 



275 

 64 

 73 

 93 



236,237 



89 

 214 

 295 



258 



(?) 



A free volatile acid. 



1881 



Textor 



(?) 



A soft resin. 



1889 



Gillette . . . 



(?)!: 



Soluble in ether. 



1889- 



VZuco 



\ Cinerarvx'folium 



(Isolated a paraffin , a phytosterol, 

 < an alkaloid, and a glucoside, 



1894 

 1890 





Roseum (?) 



[ but all were inert. 

 Not acid and not volatile. 



1890 



Eymard 



(?) 



Principally a resin. 



1890 



Schlagdenhauffen and 



Reeb. 

 Thorns 



Cineraris-foHum 



" Pyrethrotoxic acid." 



1890 



do 



An essential oil. 



1895 



De Boisse 



. ..do.... 



A resin. 



1897 





do 



A resin and volatile oil. 



1898 





do 



An oleoresin and volatile oil. 



1905 



|SatO= 



do 



A sirupy resin, "pyretol." 

 An ester, "pjTethron." 



1907 

 1909 



Fujitani 



do 



1909 



Reeb 



do 



do 



do 



" Pyrethrotoxic acid." 



1912 

 1915 



Yoshimura and Trier 



Siedler 



Cholin and stachydrin (inert). 

 Nothing definite. 









experimental work. 



Preliminary Tests. 



The coarsely powdered flowers, subjected to steam distillation, 

 yielded 0.28 per cent of a fragrant oil. This had an odor somewhat 

 like that of rosemary oil, together with a characteristic Pyrethrum 

 odor, but the amount obtained was too small to permit a chemical 

 examination. Tested against flies, this oil had only slight repelling 

 properties, and did not show the characteristic effects of Pyrethrum 

 powder. 



A steam distillation of the flowers in the presence of sodium 

 hydroxid yielded only 0.15 per cent of oil, which had a disagreeable 

 odor. Careful tests for alkaloids in the distillate gave negative 

 results. A steam distillation of the flowers in the presence of a 

 little sulphuric acid yielded 0.16 per cent oil, which lacked the 

 characteristic odor of Pyrethrum. Tested against flies, the oUs 

 from the alkaline and acid steam distillations had even less effect 

 than that obtained in a straight steam distillation. From these 

 distillation experiments it may be concluded that the substance, or 

 substances, in Pyrethrum which cause its characteristic effect upon 

 insects are not removed by steam distillation in neutral, alkaline, 

 or acid solutions. 



After being subjected to steam distillation in neutral solution, the 

 flowers were dried and tested upon roaches, when they were found to 

 be as active as before treatment. This shows that treatment with 

 steam does not decompose the insecticidal principle. 



To test the action of dilute acid and alkaline solutions upon 

 insect flowers, 50 grams of the coarsely powdered material were 

 treated with 500 cc. of solution for 24 hours, stirred occasionally, 



