INSECT POWDER qi 
powdered flowers only 0.345 gram of material was thus obtained. 
This quantity was too small for purification and chemical testing, and 
was, therefore, used for testing on insects. It was dissolved in about 
50 cc. of 95 per cent alcohol, diluted with an equal quantity of water, 
and sprayed on nasturtium plants which were infested with aphides. 
From 75 to 80 per cent of the aphides were killed. In check tests 
with 50 per cent alcohol no aphides were killed. 
The aqueous solution of sodium carbonate removed a noticeable 
quantity of a brownish-yellow material, which was obtained as a 
sticky mass after acidifying and extracting with ether. Tested 
against aphides in the same way, the material proved to be very ac- 
tive, killing 100 per cent. Extraction with sodium hydroxid solu- 
tion removed a quantity of chlorophyll and also some of the insec- 
ticidal constituents. About 80 per cent of the aphides sprayed with 
an aqueous alcoholic emulsion of the extracted material were killed. 
On evaporating the ethereal solution of the original petroleum-ether 
extract after the successive extractions with aqueous ammonium 
carbonate, sodium carbonate, and sodium hydroxid, a strong red- 
dish-orange pasty material was left. Tested on aphides, this material 
likewise exhibited marked insecticidal power, killing about 90 per 
cent of the insects. 
These tests show that the active principle can not be wholly acidic 
or phenolic; otherwise all would have been extracted by the aqueous 
sodium hydroxid solution. 
Procedure 8—The petroleum-ether percolate was not evaporated 
to dryness, but was first extracted with a saturated aqueous solution 
of sodium bisulphite to remove aldehydes, if present, and then with 
1 per cent sodium hydroxid. 
Acidifying the sodium bisulphite extract with sulphuric acid, ex- 
tracting with ether, and evaporating to dryness, gave a trace of a 
sticky varnish. This had a pleasant odor, gave a somewhat indefi- 
nite test for aldehydes, and appeared to be a polymerization product. 
Too little was obtained for satisfactory testing. Apparently, how- 
ever, a very small quantity of aldehyde is present in the petroleum- 
ether extract of insect flowers. The sodium hydroxid extract con- 
tained some chlorophyll, and in other respects closely resembled the 
sodium carbonate and sodium hydroxid extracts obtained in pro- 
cedure 2. 
The residual petroleum-ether solution, evaporated to dryness, after 
successive treatments with the bisulphite and hydroxid of sodium, 
left a sirupy, reddish material similar to the residue obtained in 
procedure 2. St 
Identification tests on the materials isolated in procedures 1, 2, and 3.— 
The extracts were subjected to several special tests as outlined in 
Mulliken’s ‘‘Identification of Pure Organic Compounds”’ and other 
standard works. Theresults showed that the petroleum-ether extract 
of the flowers of ©. cinerarizfolium, which completely removes all 
substances of insecticidal action, contains no phenols and no nitrogen- 
bearing compound, but that it consists largely of an ester or esters, 
together with a trace of aldehyde and a quantity of free acids. 
These results harmonize some of the discrepant conclusions reached 
by the previous investigators, especially Schlagdenhauffen and Reeb, 
who claimed that the active principle 1s an acid, to which they gave 
