INSECT POWDER. 79 
These tests show that the active principle can not be wholly acidic 
or phenolic in nature ; otherwise all would have been extracted by the 
aqueous sodium hydroxid solution. *■ 
Procedure 3. 
In this procedure 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. 
On acidifying the sodium bisulphite extract with sulphuric acid, 
extracting with ether, and evaporating to dryness, a trace of a 
sticky varnish was obtained. This had a pleasant odor, gave a 
somewhat indefinite test for aldehydes, and appeared to be a poly- 
merization product. The amount obtained was too small for satis- 
factory testing, but apparently a very small amount of aldehyde is 
present in the petroleum-ether extract of insect flowers. The sodium 
hydroxid extract contained a quantity of chlorophyll, and in other 
respects resembled very closely the sodium carbonate and sodium 
hydroxid extracts obtained in Procedure 2. 
The residual petroleum-ether solution, after successive treatment 
with the bisulphite and hydroxid of sodium, was evaporated to dry- 
ness, and left a sirupy, reddish material similar to the residue ob- 
tained in Procedure 2. 
Identification Tests on the Materials Isolated in Procedures 1, 2, and 3. 
These extracts were subjected to a number of special tests as out- 
lined in Mulliken's " Identification of Pure Organic Compounds" and 
other standard works, the details of which it is unnecessary to repeat 
here. By means of these tests it has been shown that the petroleum- 
ether extract of the flowers of C. cinerarisefolium, which completely 
removes all substances of insecticidal action, contains no ketones, no 
phenols, and no nitrogen-bearing compound, but that it consists 
largely of an ester, together with a trace of aldehyde and a quantity 
of free acids. 
These results harmonize some of the discrepant conclusions reached 
by previous investigators, especially Schlagdenhauffen and Reeb, 
who claim that the active principle is an acid, to which they gave the 
name of pyrethro toxic acid, and Fujitani, who claims that it is a 
neutral ester, which he named pyrethron. 
DISTRIBUTION OF THE ACTIVE PRINCIPLE IN CHRYSANTHEMUM 
CINERARI^EFOLIUM. 
It has long been known that the flowers of the Chrysanthemum 
cinerarisefolium possess insecticidal properties. The action of the 
stems is so slight that they are practically worthless as an insecticide. 
It has been generally supposed that the buds, or "closed" flowers, 
