•58 
Discussion 
The Durham color reaction (75) has become established as a rapid 
v-qualitative test for rotenone and related compounds. Like^^dse the red dolor 
test originated by Gross and Smith (50^, particularly in the Goodhue modi- 
fication (40) . is widely used in the quantitative evaluation of material 
containing these substances. Since both reactions probably depend essentially 
on the same structural grouping, the substances present in derris and cube 
which v.lll" give one of these color reactions will probably give both. The 
dehydrd reaction has not been used so v/idely as the color tests. Both the 
dehydro' reaction and the color tests have been suggested as means of evaluat- 
ing the tftxicity of rotenone-containing plants. 
At one time it was thought that rotenone and deguelin were the only 
substances r^resent in derris and cube which were determined by these reactions, 
but there is now increasing evidence that this is not strictly true. Thus, 
althou€;h Haller and LaJorge (55), ''.'orsley ( 132 ) , Tattersfield and Martin 
(l20) , and other invest i.^at or s obtained comparable results on many samples 
by the dehydro method and by the red color test, on many other samples it 
has been found that the methods do not agree. For example, on a series of 
derris roots Jones (63) obtained results th.^t ^rere substantially lower 'by 
the dehydro m.ethod than by the red color method, while results for cube roots 
were comparable. It thus appears that in many samples substances are present 
which do not give both reactions, or at least not to the same degree. 
Furthermore, nev: compounds have been found in derris which both give the red 
color test and form dehydro derivatives Cl1,56_, 831 The amounts present of 
these other compounds have been stated to be small. The recent work of 
Goodhue and Haller (4l) , however, presents the possibility that large amounts 
of substances other than rotenone and deguelin may be determined by both the 
red color test and the dehydro reaction. On the other hand, it is possible 
that the deg-jelin may not all be present in such a form as to be determined 
by the racemization method. The earlier work of Haller and LaForge (55) bad 
already indicated that not all the deguelin was present in a single form. 
Only further work can give a clear understanding into the cause of the con- 
siderable discrepancies between this and the earlier methods. In the mean- 
time results by any of these methods should be considered as essentially 
emoirical. 
