PYRETHRUM POWDERS 367 
Doctor Dade continued to experiment with this remedy after his return from an 
unsuccessful attempt to capture General Aguinaldo, and found that the addition 
of one part oil of bergamot to sixteen of kerosene imparted an odor scarcely ob- 
jectionable, and at the same time added sufficient body to the kerosene to pre- 
vent evaporation in less than six to eight hours. After that, when the soldiers 
had to leave the post, and after it became impracticable to carry cans with them 
in the field for a long or protracted march, this mixture was used with the result 
that the list of malarial patients was noticeably shortened. The oil of bergamot 
was hard to obtain and is too expensive to be used wholesale, but the soldiers 
rarely objected to the odor of kerosene and the bergamot was not continued. 
In moist tropical regions where one perspires profusely, the oily mixtures 
on the skin considered under this heading are transient in their effects. Under 
these circumstances they should be applied rather liberally to the clothing, 
particularly about the neck and wrists. 
SMUDGES AND FUMIGANTS. 
Hunters and campers have been in the habit of using almost anything that 
will make a dense smoke as a smudge to drive away mosquitoes. In Bermuda, 
fresh cascarilla bark is burned for this purpose, and elsewhere other green bark 
and vegetation. For household use, however, a number of different substances 
have been tried. 
PYRETHRUM OR CHRYSANTHEMUM. 
For many years finely ground powders known as pyrethrum powder, chrys- 
anthemum powder, Persian insect powder, or Dalmatian insect powder, have 
been used to kill insects. They became famous for their insecticidal effects long 
before their composition was known. Their use seems to have originated in 
Asiatic countries beyond the Caucasus Mountains. The powder was sold at 
high price by the inhabitants and was brought by merchants to Russia and 
western Huropean countries. The nature of the powder was kept a secret until 
the beginning of the last century, when an Armenian merchant, Mr. Jumtikoff, 
learned that the powder was obtained from the dried flowerheads of certain 
species of composite plants of the genus Chrysanthemum (Pyrethrum) growing 
abundantly in the region now known as Transcaucasia. The son of Mr. Jumti- 
koff began to manufacture the article on a large scale in 1828, and since then the 
pyrethrum industry has steadily grown and now the export in dried flowerheads 
from that part of the country is very important. 
The species grown commercially in the Transcaucasian region is Chrysan- 
themum roseum. The species grown in Dalmatia is C. cinerariefolium, and the 
crop in Dalmatia, Montenegro and Herzegovina is now the principal source of 
the powder in commerce. Thirty years ago it was considered the most valuable 
export of Dalmatia. The best powders are made from the dried flowerheads of 
these plants. The essential principle resides in the oleoresins, which are 
fugitive, so that the strength of the powders disappears with age or exposure. 
Powders imported from Europe are not so strong as powders made in this 
