INSECT POWDER. 77 
Procedure 1. 
For further separation of the materials present in this residue, the 
entire material extracted by the petroleum ether was saponified by 
boiling with alcoholic potash (22 grams of potassium hydroxid and 600 
cc. 95 per cent alcohol to 32 grams of extract). The boiling was con- 
tinued for 75 minutes, the alcohol removed by evaporation on the 
steam bath, the residue taken up in water, and the alkaline solution 
extracted with ether. The ethereal extracts, which were of a beautiful 
reddish-yellow color, were combined, washed with a little water, 
dried over calcium chlorid, and the ether removed by evaporation at 
room temperature in a current of air. A mass of reddish-yellow 
powder was left. On recrystallizing this powder from alcohol, the 
first recrystallization removed all of the red color, and the second all 
but a trace of the yellow color, leaving crystals of a very pale yellow. 
The melting point of these crystals (167° to 168°) and tests for a 
phytosterol showed it to be a phytosterol-like substance. Tested 
upon insects (roaches, ants, and aphides), it proved to be inert. 
The mother liquors from the recrystallizations were evaporated to 
dryness in a vacuum desiccator over sulphuric acid. More of the 
phytosterol-like substance was obtained, but nothing else. This was 
also found to be inert against the insects mentioned. The insecti- 
cidal principle of Pyrethrum flowers is not, therefore, in the non- 
saponifiable portion of the petroleum-ether extract. 
The solution from the saponification after extraction with ether 
was made slightly acid with sulphuric acid, and again extracted with 
ether. These extracts were very dark red, almost black. After 
washing with a little water, drying over calcium chlorid, and evapora- 
ting the ether at room temperature in a current of air a sticky resin 
was left. Special tests were made for phenols in this material, but 
the results were negative. Tests on small portions with various sol- 
vents failed to yield any crystalline product. 
The whole of the saponifiable portion was then dissolved in U. S. 
P. ether, and about twice its volume of petroleum ether added. This 
precipitated a very dark, sticky resin, which was filtered off. Tested 
upon aphides, this resin proved to be inert. 
The filtrate from this resin, which contained the fatty acids, was 
evaported to dryness, leaving a soft, yellowish, oily, sour-smelling 
residue. This material was shown to contain acetic and other fatty 
acids, together with a pungent-tasting oily substance which was pres- 
ent in too small an amount for further investigation. When sprayed 
upon aphides feeding on nasturtium plants, the fatty acids injured 
the leaves of the plants, but the aphides were unaffected. 
These tests show that saponification with alcoholic potash produces a 
chemical change which destroys entirely the insecticidal action of 
