66 BULLETIN 824, IT. S. DEPARTMENT 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 aikaloidal 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 
slightest harmful action on the human organism. 
Rother (234), in 1876, recorded the results of some tests made upon 
Pyrethrum, but the species he used is not indicated. The absence 
of alkaloids is proven, and the active principle is stated to be a glu- 
coside, called persicin, which can be split up into glucose and an 
inert body called persiretin. He also isolated a yellowish, bitter 
resin, designated as persicein. Later, Rother (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 degree 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. 
SemenofT (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 was 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- 
