- 11 - 
The authors also reported their ovm results on 81 Scunples of derris. 
Results using ether were in close agreement with those using benzene, "but 
the , time required for exhaustive extraction with ether was 2 days and 3 
nights, whereas benzene required only 36 hours. 
In discussing the determination of total extract Mei.jer (86) in 
1937 recommended slow percolation of derris powder with ether in a Soxhlet. 
This was accomplished by placing the powder in the extraction tube of the 
apparatus without using a thimble. He also stated that drying of the 
extract, after removal of most of the solvent, was better accomplished at 
40° C. under reduced pressure thaji by the usual drying at 100° C 
Jones and Graham (7l) in 1938 determined total benzene extract by 
Soxhlet extraction of 5-gm. samples. ..,.....-...;■;■' 
The determination of total-extract content was studied by Jones and 
Sullivan (76 X in 1Q38, in an endeavor to select the solvent and method 
that would most, readily extract all the toxic substances, from derris and 
cube roots together with the least amount of nontoxic material. The total- 
extract content of several samples was datermined by several procedures 
with various solvents. Successive extracts of some of the marcs with 
acetone, methyl alcohol,. and water were tested against mosquito larvae. 
In 7-hour Soxhlet extractions of 5-gm. samples the percentages of material 
extracted by benzene, carbon tetrachloride, and ether were generally lower 
than by .chloroform, ethylene dichloride , trichloroetnylene , and ethyl 
acetate, which gave values of about equal magnitude. Acetone generally 
extracted more material and methyl alcohol considerably more than did the 
other solvents. When samples were extracted with ether or benzene for an 
extended length of time, the amount of material removed agreed with that 
extracted by chloroform.- Acetone extracts of marcs from extraction with 
chloroform were in general nontoxic. I.'ethyl alcohol and water extracts 
following this were completely nontoxic. Acetone extracts of marcs from 
benzene and ether .extractions were toxic. Thus, of the solvents tested, 
chloroform appeared to be -.the most satisfactory from the standpoint of 
selective extraction of the. toxic material. Results by the multiple- 
extraction procedure and by the aliquot procedure with chloroform at room 
temperature were in agreement with those by ^oxhlet extraction. Because 
of its convenience, particularly when rotenone wag to be determined by 
the same method, the aliquot procedure v/as suggested as the most suit- 
able for determination of total-extract content! 
Rowaan and Van Duuren ( 108 ) in 1938 suggested chloroform extraction 
at room temperature for the determination of total-extract content of 
derris and cube root. 
Mei.jer (87) in 1938 showed the effect of drying the sample at 
elevated temperatures on tne amount of ether extract obtainable. 'Pnus, a 
sample of powdered derris root which before being heated contained 23.6 
percent of ether extract gave 19.1 percent after being heated at 60° C. for 
2 hours and only 14.4 percent after being heated at 80° C. for 2 hours. 
He concluded that heating above 50° C. before analysis should be avoided. 
