INSECT POWDER - 67 
The crystalline alcohol pyrethrol first obtained by Fujitani (89) 
and described by Yamamoto (S3/) was not toxic, nor could a toxic 
product be prepared by combining it with pyrethronic acid. The 
results of Yamamoto’s work indicated that pyrethronic acid is one 
of the components of the active principle of insect powder. 
More recently Yamamoto (S33) has described his work on the 
products of dry distillation of C. cinerariefolium. The material was 
distilled at a temperature of 260° to 280° C. About one liter of 
distillate was obtained from 3,500 grams of the powdered flowers. 
The distillate gave an acid reaction and from it were isolated acetic 
and propionic acids, acetic and propionic aldehydes, methyl, trime- 
thyl, butyl, and amyl amines, pyridine, and a higher homologue of 
yridine whose picrate melted at 84°. These acids and bases seem to 
ie present in the combined form in the flowers. | 
A study was made of the insecticidal properties of homologous 
acids, esters, and bases. Of the common fatty acids, formic was 
the most toxic. Butyl amine showed the greatest toxicity of the 
monoalkyl amines. In general, the tertiary amines, especially ter- 
tiary amyl amine, were the most effective. The insecticidal power 
increased with the molecular weight among the amines having boil- 
— ing points below 80°. 
Abbott (S71), Chevalier (S83), Chevalier and Dantony (S84), Cheva- 
lier and Mercier (S5), Costa (S7, SS), Gattefossé (S75), Juillet (S17, 
S18, S19, S20), and Zeigler (S34) have also studied the active con- 
stituents of insect powder. 
EXPERIMENTAL WORK 
Work Done 1n 19177 
Preliminary tests —The coarsely powdered flowers, subjected to 
steam distillation, yielded 0.28 per cent of a fragrant oil. This 
had an odor somewhat like that of rosemary oil and like the char- 
acteristic Pyrethrum odor. The quantity obtained was too small to 
permit a chemical examination. Tested against flies, this oil had 
only slight repelling properties, and did not show the characteristic 
effects of Pyrethrum powder. A steam distillation of the flowers in 
the presence of sodium hydroxid yielded only 0.15 per cent of an 
oil which had a disagreeable odor. Careful tests for alkaloids in 
the distillate gave negative results. A steam distillation of the 
flowers in the presence of a little sulphuric acid yielded 0.16 per cent 
of an oil which lacked the characteristic odor of Pyrethrum. Tested 
against flies, the oils from the alkaline and acid steam distillations 
had even less effect than that obtained in a straight steam distilla- 
tion. ‘These experiments indicate that the substance, or substances, 
in Pyrethrum which cause its characteristic effect upon insects are 
not removed by steam distillation in neutral, alkaline, or acid solu- 
tions. 
After being subjected to steam distillation in neutral solution, the 
flowers were dried and tested upon roaches. They were as active 
as before treatment, showing that treatment with steam does not 
~ decompose the insecticidal principle. 
To test the action of dilute acid and alkaline solutions upon 
‘insect flowers, 50 grams of the coarsely powdered material was 
“\ 
on as! 
PS ee a 
7 Conducted by R. C. Roark. 
