62 BULLETIN 824, U. S. DEPARTMENT OF AGRICULTURE 
moved by hydrogen sulphid. After filtration, the liquid was concen- — 
trated to about 2 liters, boiled for some time with dilute sulphuric 
acid, filtered again, and boiled until no more resinous matters were ~ 
formed. The liquid was then decolorized with animal black, and an 
excess of the double iodid of potasstum and bismuth added. This 
precipitated a heavy bright red crystalline powder. From this the 
alkaloid was obtained. According to Zuco this is a colorless sirup 
soluble in water and in alkalis and in ethyl and methyl alcohol, 
but not in ether, chloroform, or benzene. The base is described as 
being optically inactive and physiologically innocuous. The work 
of Zuco thus shows that the active insecticidal agent of Pyrethrum 
flowers is not alkaloidal in nature. 
Eymard (77), in 1890, distilled a mixture of insect powder with 3 
parts of water. The distillate was slightly opaline, held in suspen- 
sion a small quantity of “essence,’’ and presented a strong and 
characteristic odor of Pyrethrum flowers. Tested upon ants and © 
other insects, however, the distillate was found to have no effect, 
from which Eymard concludes that the essential oil is not the active 
insecticidal agent of insect powder. | 
An ether extract was made, deep yellow and strongly odorous. 
It gave up nothing to water, but was completely soluble in 95 per 
cent Hicakol and in alkalis. From alkaline solution it was precipi- 
tated by acid. From110 grams of insect powder Eymard obtained 
5.6 grams of ether extract. This was dissolved in alcohol and treated 
with silver nitrate, which precipitated the fatty acids as silver salts, 
while the silver resinates remained in solution. The ether extract 
was in this manner shown to consist of 3.8 grams fatty bodies and 
1.8 grams resinous matter. Insects placed upon a piece of paper 
impregnated with this resinous matter manifested extreme agitation 
and died in about 5 minutes. After exhaustion with ether, the 
insect powder was successively extracted with 95 per cent alcohol, 
cold distilled water, and boiling distilled water, but no toxic sub- 
stances were obtained. No alkaloids were detected. Eymard con- 
cludes that the toxic principle of Pyrethrum is found m the part 
soluble in ether, and more especially in the resm. However, it is his 
opinion that several factors unite in the réle of insecticide, as he found 
that the isolated active principle worked less actively than the 
original powder. : 
Schlagdenhauffen and Reeb (245), in 1890, distilled 250 grams of 
the flowers of Pyrethrum in a current of steam, collecting 750 grams 
of distillate. ter filtering through a wet filter, the distillate was 
extracted with ether and the ethereal solution was separated, filtered, 
and evaporated ata temperature not exceeding 30° C., A few drops 
of a green oil texic to insects were thus obtained. No alkaloid 
was present in the oil. The aqueous part was acid, but had no — 
injurious effect upon insects. The authors obtained an acid which 
was toxic to insects, by exhausting with alcohol acidulated with 
hydrochloric acid, drying, exhausting with ether, shaking the ethe- 
real solution with ammoniacal water, evaporating to dryness, again — 
taking up in water, and filtering. The filtrate contains the am- 
monium salt of the toxic acid. This acid was also obtained by 
extracting with alcohol, neutralizing exactly with a solution of 
potassium hydroxid, evaporating gently to dryness, taking up in 
water, filtering, and treating the filtrate with a solution of tartaric 
acid, and extracting the liberated acid with ether. This toxic acid 
