70 BULLETIN 824, U. S. DEPARTMENT OF AGRICULTURE 
very pale yellow. The melting poimt of these crystals (167° to 168°) 
and tests for a phytosterol showed it to be a phytosterol-like sub- 
stance. 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 
evaporating 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. 
solvents 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 
evaporated 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 a quantity for further investigation. When sprayed 
upon aphides feeding on nasturtium plants, the fatty acids injured 
the leaves of the plants, but the aphides were unafiected. 
These tests show that saponification with alcoholic potash pro- 
duces a chemical change which destroys entirely the insecticidal 
action of the material. That saponification with alcoholic potash 
effects chemical decomposition in some of the compounds present is 
also shown by the fact that petroleum ether added to the U. S. P. 
ether solution of the saponifiable portion precipitates a resin, whereas 
all the material before saponification was soluble in petroleum ether. 
Procedure 2.—Since saponification with alcoholic potash destroys 
the insecticidal action of the material extracted by petroleum ether, 
another procedure was adopted. A petroleum-ether extract was 
obtained as before, evaporated to dryness, and taken up in U. S. P. 
ether. This ethereal solution was successively extracted with aqueous 
solutions of ammonium carbonate, sodium carbonate, and sodium 
hydroxid made up on the basis of 10 grams of salt to 100 cc. of solu- 
tion. The ammonium carbonate solution assumed a light yellow 
color when shaken with the ethereal solution of the extract. Emul- 
sions which were difficult to separate formed. After repeatedly ex- 
tracting with ammonium carbonate and washing with water, the 
ethereal solution was separated and reserved for the sodium ear- 
bonate extraction. 
The ammonium carponate solution was made acid with sulphuric 
acid and shaken with ether, which slowly and apparently incom- 
pletely took out the yellow color. On evaporating this ether extract 
to dryness, after washing and drying over calcium chlorid, a few 
greenish-yellow, oily, sticky drops were left. From 1,920 grams of 
