68 
acetone extracts of certain derris roots with little or no rotenone by 
crystallisation were dextrorotatory. There vas no agreement oetween the 
value obtained by crystallization and the values obtained from the optical 
rotatory powers of either acetone or benzene extr-'-cts. A further calculation 
based on optical rotatory poP©r which used the rotations of both acetone and 
benzene extracts wa« nade by Jones. It was based on the assuT.ption that the 
optical rotatory power of all the rotenonelike com-..our.ds oresent was greater 
in benzene than in acetone to the same degree as ifas that of rotenone, and 
that the rotation of the oth r optically active material \-/as the same in both 
solvents. All values by this method were "marlcedly higher thao values obtainedb 
crystallization. It was concluded that the ootical rotatory pover could not 
be rccomiTiended as a means of evalu.?tion of derris and cube root. 
One of the laboratories particioating in the collaborative analysis of 
derris report«^d by Koolha--?s and Meijer (see p. 35 J in 1937 used the oolari- 
metric method of Danckwortt, The use of this method for the determination 
of rotenone was criticized by the authors of the report because of the general 
lacs of knowledge of the significanc3 of optical activity and of the propor- 
tion, of other constituents present. 
Vorsley (l32) in 1937 studied the use of optical rotatory pow-ir as a 
means of assessing the toxicity of dorris root. The dritrd cixtract from 
hot percolr-tion of the root with cthj'-l acetste Was dissolved in benzene and 
the concentration of the solution adjust, d so that the angle of rotation 
in a 200-mm, tube was about )22 degrees. Concentrations bet'A'.^cn 25 and 200 
gm of original sample in 25 cc. of benzene were involved. Direct extraction 
with benzene in a Sorhlet gave the sajnc results. From a curve for the optical 
rotation of pure rotenone a value was read off corresponding to the angle 
obtained as described in 'Vorsley's method for rotenone .dctermin?.tion (l30). 
Because in most samples this value agreed rather closely ^-rith th-?t for 
dehydro compounds, Worsley used the term "optical dohydro conipo^onds." In a 
subsequent article Worsley (l33) proposed the term "optical constituent?^ " 
instead of "optical dehydro compounds" for the value described in the previous 
work. He also proposed the use of the reciprocal of this value for toxicity 
como;^risons. 
Guillaurae and Procschel (54) in 1937 st-^ted that the polarimetric 
method was usad in CJermany, but that investigators in other countries found 
it gnve too high r: suits. 
Rowapn and Van Duuren ( 108 ) in 1938 confirmed in general the observations 
of Jones (65 ) on the optical activity of derris and cube extracts, particular- 
ly with regard to the dextrorotation of derris extracts that gave no rotenone 
by crystallization . 
Thung (123) in 1939 stated tha.t in the analysis of derris powder a 2- 
gm. sample was extracted by shaking repeatedly with 53 cc. of benzene during 
24 hours. The optical rotation of the filtered extract was determined in a 
20CLmm, tube (0.5^ V. • l percent rotenone). 
