INSECT POWDER 61 
end of the tube being kept cool with a wet cloth. The insects were allowed to 
remain for a few minutes after the boiling, but showed no signs of being affected 
by the treatment. 
Another tube was then prepared in which were confined other cynipids in a 
manner similar to the preceding, and the tube was held over the flame of an al- 
cohol lamp and constantly shaken until the powder was entirely browned, care 
being taken not to burn it. The insects were unhurt by this treatment. 
Then a quantity of powder was put in a tube and held in the flame of a lamp 
until the tube was filled with fumes. These fumes were poured over into another 
tube in which was an ichneumon, on which they took immediate effect and death 
ensued in a very few minutes. 
Next, three ichneumons were inclosed in separate tubes. One was shaken up 
with a small quantity of fresh Pyrethrum powder, one with a small quantity 
of the browned powder spoken of in the second preceding experiment, and one in 
a small quantity of the partially burned powder spoken of in the preceding 
experiment. In each case the insect was killed, the fresh and the browned articles 
acting alike, and the partially burned powder acting somewhat slower. 
Three grams of the powder were then put in about 90 cc. of water in a retort 
and boiled for one-half hour, the vapor being caught and condensed in a receiver. 
Soon after boiling began a slight odor was noticed escaping about the mouth of 
the receiver which the neck of the retort did not quite fill. A eynipid was en- 
tangled in a bit of cotton and crowded into the opening, where it remained for 
12 minutes without being affected. 
About one-half of the liquid was sent over in the above experiment, and the 
distillate was clear, colorless, and almost tasteless and odorless, there being a 
slight taste resembling steeped hay. The distillate and the residue were used to 
compare their insecticidal properties with one another and with fresh powder 
extracted in cold water for 24 hours. The results of these experiments were that the 
distillate used pure killed but a very small percentage of the lice treated and that 
the residue was as efficient as the same quantity of powder extracted in cold water. 
Gillette found that ether extracted all the insecticidal principle 
from Pyrethrum, as the extracted powder when dusted upon insects 
had no effect. The greater part of the ether extract would dissolve 
readily in water, and this water solution affected insects exactly as 
if they had been treated with Pyrethrum. 
Zuco (296), in 1889; made an ethereal extract of the flowers of 
Chrysanthemum cinerarizfolium. After repeated treatment of this with 
aqueous and alcoholic potash asubstance was left which formed yellow 
crystals and had a melting point of 70° to 100° F. After repeated 
recrystallization from cold ether a paraffin, C,;H3., of melting point 
64°, was obtained. This dissolved freely in ether, benzene, chloro- 
form, and moderately hot alcohol, but was almost insoluble in cold 
alcohol. The portion remaining in cold ether was recrystallized 
until the melting point was above 150°. Pure cholesterin was pre- 
pe from either the acetyl or benzoyl derivative of this substance 
by the action of alcoholic potash. The cholesterin thus obtained had 
a melting point of 183°; the melting point of its acetyl derivative 
was 223°, and that of the benzoyl derivative, 246°. It dissolved 
freely in ether, benzene, and chloroform, and sparingly in hot alcohol, 
and gave all the reactions for cholesterin. 
In 1890, Zuco (297, 298) obtained a glucoside and also an alkaloid 
from the flowers of Chrysanthemum cinerarizfolium. He described 
the glucoside as crystalline, but not enough was obtained for proper 
investigation. Later, Zuco (299) described the method he used in 
obtaining the alkaloid, called chrysanthemine, from Pyrethrum 
flowers. Ten kilograms of flowers was boiled in distilled water for 
two or three hours and filtered throughcloth. The residue was pressed 
and treated again in thesame manner. Theextracts were evaporated 
down to 30 liters, treated with neutral lead acetate and basic lead 
acetate, neutralized with soda, and filtered, the excess of lead being re- 
