66 BULLETIN 824, V. S. DEPAETMENT OF AGRICULTURE. 



Hanamann (114), in 1863, referred to previous work by Heller and 

 Kletzinsky, stating that they found genuine Persian insect powder 

 to contain no narcotic or alkaloidal plant poisons or poisonous min- 

 eral substances, but only ethereal oil and santonin, as the active 

 insecticidal constituents. From his own experiments Hanamann 

 concluded that Pyrethrum flowers contain no poisonous acting 

 alkaloid or santonin, but mostly indifferent substances, and that 

 only the ethereal oil in concentrated form can have any harmful 

 effect. He stated that genuine insect powder can not have the 

 shghtest harmful action on the human organism. 



Pother (234), in 1876, recorded the results of some tests made upon 

 Pyrethrum, but the species he used is not indicated. Th^ absence 

 of alkaloids is proven, and the active principle is stated to be a glu- 

 coside, called fersicin, which can be split up into glucose and an 

 inert body called persiretin. He also isolated a yellowish, bitter 

 •resin, designated as persicein. Later, Pother (235) states that per- 

 sicin is not a glucoside and that the glucose reaction is due to glucose 

 or a gum preexisting in the powder. Thus the matter is left in a 

 state of confusion. 



Jousset de Bellesme (63), 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. 

 As he expresses it, after having submitted Pyrethrum to the treat- 

 ment proper to extract an alkaloid, he obtained a crystallized prin- 

 ciple which enjoyed to a high degi*ee the toxic properties of the plant. 

 This account of the work of de Bellesme is simply an abstract of an 

 address he made before the Biological Society of Paris. Statements 

 are made, but no experimental proof is given. 



Semenoff (253), in 1877, obtained flowers of Pyrethrum, presum- 

 ably Pyrethrum roseum or carneum, from Caucasia, near the Turkish 

 boundary. Dried at 25° C, the flowers were as active against insects 

 as commercial insect powder. An essential oil was obtained by steam 

 distillation, but proved to be inactive. By distillation in an alkaline 

 solution a very small amount of an alkaloid was obtained. By 

 macerating 1 pound of the flowers with 5 pounds of ether for 5 days, 

 and evaporating the extract, a mixture of resin, oil, wax, and acids 

 was obtained, which on steam distillation yielded an ethereal oil 

 that killed insects. 



Hager (111), in 1878, reported that the insecticidal activity of the 

 flowers of Pyrethrum carneum and roseum was due to two substances. 

 One v/as 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- 



