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Hur.il (208), in United States patent 2,037,599, issued July 20, 
1937, applied for September 8, 1932, assigned to Stanco, Inc. , claims 
an insecticide including water, a suitable oil and finely powdered 
natural parts of a plant selected from the group consisting of derris 
and cube root containing an inherent emulsifier and properties toxic to 
insects. 
The following specific example is given of one way of carrying 
out the invention: Spent pyre thrum flowers containing approximately 
10 percent oil residue extract from a previous extraction of the fresh 
flowers with oil are pulverized and mixed with water in the proportion 
of 1 part of flowers to 3 parts of water, and about 2 percent of cresylic 
acid (based on the whole mixture) is added as a preservative. This 
mixture is, after proper agitation, suitable as a stock emulsion which 
will he ready for use with mere dilution with water. Ground derris or 
cube root can be satisfactorily used in a composition similar to the 
above instead of the spent pyrethrum. 
Simanton (378), in U. S. Patent 2,089,766, issued August 10, 1937, 
applied for March 7, 1936, assigned to Gulf Research and Development 
Company, claims an improved insecticide comprising in stable admixture a 
petroleum fraction, a substance chosen from the class consisting of 
ethylene glycol monoethyl ether acetate and diethylene glycol monoethyl 
ether acetate, pyrethrins and at least one of the active toxic ingredients 
of derris and cube. 
Among the solvents commonly employed as blending agents in combi- 
nation with petroleum naphthas are ethylene dichloride, carbon tetrachlo- 
ride, acetone, camphor, sassafras oil, benzol, and chloroform. These 
solvents are each and all objectionable for a variety of reasons, chief 
of which is that their odor is distinctly disagreeable. 
Ethylene glycol monoethyl ether acetate and diethylene glycol 
monoethyl ether acetate are each completely miscible with the petroleum 
fractions known as naphthas and are also miscible to a more limited extent 
with higher boiling petroleum fractions. 
In one actual embodiment of the invention the patentee prepared 
an insecticidal solution by first forming a 5 percent solution of crystal- 
line rotenone in diethylene glycol monoethyl ether acetate and then adding 
one part of this solution to 100 parts of a petroleum naphtha extract of 
pyrethrum flowers prepared by extracting 1.2 pounds pyrethrum flowers 
with a deodorized petroleum naphtha. The resulting product was a stable, 
non-volatile, substantially odorless solution of excellent insecticidal 
properties. When tested according to the Peet-Grady method the solution 
repeatedly gave a knock down value of 98 and a kill of 85. 
Coe (85), in U. S. patent 2,090,109, issued August 17, 1937, applied 
for November 15, 1933, claims a composition of matter comprising a sus- 
pension of a powdered insecticide of plant origin subject to deterioration 
by ordinary light, in a colored globule-forming liquid of adhesive tendency 
and nonrepellent to insects, the color of the globule-forming liquid 
