- 34 - 
"The contests of the crucible pre then broken up with a spatula 
ana thoroughly mixed, and a 1-gram sample is placed in a 50-ce. F.rl- 
emeyer flask where it is treated with 10 ce. of a] core], which has 
been saturated with rotenone at room cempe nature. The flask is swirled 
for a few minutes and then tightly stoppered and set aside at the sane 
temperature for 4 hour?. The mixture is then filtered at the bane 
temperature through a weighed Gooch crucible with filter-paper disk. 
The crystals are rinsed from the flask and washed under ruction with 
the solution of alcohol saturated with rotenone at the temperature of 
the recrystallizatioh. About 5 c.:. are usually required for this. 
Suction is applied for about 3 minutes, and then the material is dried 
at 105° C. to constant weignt, or for about 1 hour. The weight in 
grams is multiplied ~by the weight of crude solvate, and to the product 
is added 0.07 gram, representing the correction for rotenone held in 
solution in the 25 cc. of carbon tetrachloride "used in crystallization. 
If any pure rotenone was added, its weight must be subtracted from the 
value obtained. This gives the weight of "pure" rotenone contained 
in the extract of the 25-gran root sample." 
Cassil (66) in 1937 reported that the G-oss-Siith-Gaoc'hue (J. A. 0. A. C . 
19: 218-120. 1935) red-color test for micro amounts of rotenone previously 
developed in the Division of Insecticide Investigations can be applied to the 
study of derris cr cube residues on cabbage. OhlorOphyll and wax from the 
outside leaves complicated the recovery of the rotenone, but the procedure 
finally developed overcame the difficult". It was found that cabbages from a 
plot that had received a total of 94 pounds of derris dust (9.4 pounds of 
derris) in six applications, retained, 5 days after the last dusting, 0.006 
grain derris per pound, equivalent to 0.8 p. p.m. Five-sixths of this was on 
the four outer leaves, which normally are discarded before the cabbage is sold 
to the retail trade. 
According to a re-port of the H&adelsmuseum of the Koloniaal Instituut 
of Amsterdam (352) in 1937, Lonchocarpus powder is only l/2 to 2/3 as active 
insecticidally as derris powder. Examination of 19 samples of powder repre- 
sented to be derris powder showed- 10 samples to consist exclusively of derris 
powder, 3 samples to be mixtures of derris and Lonchocarpus, and samples to 
consist solely of Lonchocarpus powder. Examination of 7 samples of derris 
dusting- mixture showed that all 7 contained derris powder. This information 
is also given by Spoon (389). 
The United States Department of Agriculture, Food and Drug Administra- 
tion (425), in its annual report for 1937 stated that more satisfactory methods 
for determining rotenoro in Ferris anr 1 cube, both i*i the root powder and in 
mixtures of these powders with sulphur, had beer developed. 
Jones and Graham (228) in 1933 presented the results of a study of the 
relative merits of various solvents for the extraction of rotenoro from derris 
and. cube. Tests were made with chloroform, benzene, acetone, ethyl acetate, 
carbon tetrachloride, ethylene dichloride, brichloro ethylene and an azco tropic 
mixture of benzene-alcohol. The moisture content of the samples tested ranged 
from 4.9 to p. 5 percent. The authors draw the' following conclusi ns from 
their work: 
