_61 
the use of secondary standards where necessary. Difficulty was #ncountered 
in matching the colors from the cube samples, and the use of the alkali- 
soluble fractions of the extracts did not improve the color matching. The 
amount of alkali -soluble material was determined by the method previously 
used (69). 
Martin (83) in 1940 made determinations of alkali-soluble material, 
or of "toxicarol fraction," on several samples of derris. The method was 
similar to that used in previous work (84) except that extraction of the 
ether solution was made first with one lot of 2-percent and then with 
two lots of 5-percent potassium hydroxide. As mentioned under the sections 
on Rotenone and Deguelin, a mixture of ether with 25 percent of benzene 
was employed as the solvent for extracts of high-rotenone roots. It was 
also stated that the percentpge of "toxicarol fraction" removed by the 
potash could be determined from the difference in the percentages of original 
and "neutral" (alkali-insoluble) resins. 
Discussion 
Both the determination of alkali-soluble material and the ferric 
chloride color test must be considered to give only empirical values. It 
is probable that in Sumatra-type derris roots both these methods give 
reasonably close approximations of the toxicarol plus, suraatrol content. In 
other samples of derris and particularly in cube samples large amounts of 
interfering substances are undoubtedly present. Since the ferric chloride 
test was proposed an additional phenol, malaccol, has been isolated from 
derris (88) . Rowaan and Van Duuren ( lOS ) state that toxicarol has not 
yet been isolated from Loncho carpus , (cube), and attempts to isolate this 
compound from cube root in the laboratories of this Bureau have been un- 
successful. Nevertheless, the samples of cube examined by Jones (68) gave 
ferric chloride values equivalent to 1.5 to 2.8 percent of toxicarol, 
presumably due to other phenolic bodies, and contained 2.8 to 5.0 percent 
of alkali-soluble material. 
The method of Rowaan and Van Duuren (l08)^ based on the separation of 
inactive toxicarol, should be subject to less error from interfering sub- 
stances. However, the accuracy of the scheme may be questioned when only 
small amounts of toxicarol are present. 
MIS-CELIANEOUS COLORIMETRIC DETEILMI NATIONS 
Sulfuric Acid-Nitrite Color Reaction 
In 1899 Sillevoldt (ll4) found that his "derrid," vhich undoubtedly 
contained a high percentage of rotenone, gave a brown-violet color with 
concentrated sulfuric acid. Danckv/ortt, Budde, and Baumgarten (25) in 1934 
found that sulfuric acid followed by a small amoirnt of sodium nitrite gave 
an intense red-violet color with rotenone. This finding sutgests that 
Sillevoldt 's acid contained a trace of nitrite. V-Tien the test was applied 
to derris root, a 0.5-gm. sample was shaken with 5 cc. of chloroform and 
1 to 2 drops of the filtered extract were evaporated on a wateh glass. To 
