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"Value? for 'rotenone' equivalent to the combined optical 
rotatory powers of both acetone and benzene extracts of derris and 
cube roots gave an approximate measure of the insecticidal effec- 
tiveness of these materials to houseflies. Values calculated from 
the rotation of benzene extracts did not agree with toxicity su well 
as did the combined values, and in about half the samples results 
derived from the optical activity of acetone extracts were widely 
different from the toxicity values. 
jI Since a method has already been proposed for calculating the 
approximate toxic value to houseflies of derris and cube roots based 
on the rotenone and total extractive contents, which is both simpler 
and less open to question', the use of optical rotatory power cannot be 
recommended as a means of evaluation. 
"From the chemical standpoint the results indicate that op- 
tically active constituents other than rotenone and deguelin were prob- 
ably present in the samples of derris and cube tested. Dextrorotatory 
materials were undoubtedly present in the samples of derris root con- 
taining no rotenone, and possibly in other samples. The use of opti- 
cal rotation should prove of considerable value in further chemical 
study of the components of extracts of derris and cube roots." 
Ten samples of cube ranging in actual rotenone content from 0.8 to 
12.1 percent and in total acetone extract from 14.1 to 25.4 percent were used 
in these studies. 
Spoon (390) et al., of the Koloniaal Instituut of Amsterdam, in 1937 
reported a means of distinguishing powders made from Derris and Lonchocarpus 
by the characters of the starch grains. Besides the shape also the size of 
the grains is characteristic for both genera. An exact description and figures 
are given. For 1,063 measured grains of Derris starch the average length is 
6.38 microns +0.1; for 1,197 measured grains of Lonchocarpus starch the aver- 
age size is 9.P0 microns +0.2. A drawing shows the size of the grains. By 
means of the differences described it is -possible to distinguish with cer- 
tainty between Derris powder and Lonchocarpus powder as well as between dusts 
for insocticidal purposes, prepared with both roots. It is claimed that mix- 
tures can be examined and the average percentage of Lonchocarpus powder mixed 
with pure Derris powder detected. 
Seabcr (370) in 1937 reported analyses of derris, barbasco and timbo 
for rotenone, using chloroform, carbon tetrachloride, trichloro ethylene and 
ethyl acetate as solvents. In all cases chloroform gave higher results. 
Seaber suggests that the best method for the determination of rotenone is to 
extract with cold chloroform (Beach's method), crystallize from carbon tetra- 
chloride, determine the purity of the solvate by polarization, and report the 
percentage of pur^, rotenone. 
Graham (170) , Referee on Insecticides for the Association of Official 
Agricultural Chemists, in 1937 reported that during 1936 he investigated a 
number of methods for the determination of rotenone in derris and cube and that 
their collaborative study would probably be undertaken next year. 
