- 24 - 
a 10-gm. sample of hif:h rotenone content could be completely extracted 
v/ith 200 cc. of hot ethyl acetate in about 45 ininates. Hooto of lov/er 
content, of which larger samples were used, required more solvent anri 
longer time but seldoM over 2 1/2 nours. Worsley found it advisable to 
add s^officient rotenone before crystallisation from carbon tetrachloride 
to bring tne ratio of rotenone to total extract up to 40 percent. The 
p-iority of tne carbon tetrachloride solvate prepared by the author's method 
was stated to range from 92.5 to 97 percent and averaged 94.7 percent , 
as .-"ud^ed by the alco:aol recovery of Catm and Boam. The rotenone obtained 
^vfter the alcohol treatment was found by measurements of its optical rota- 
tion to range in purity from 98 to 99.9 percent, v;ith an average of 99.2 
percent. On the basis of the latter value the a.verage purity of the crude 
solvate became 94 oercent. Worsley pi oposed usin^: this value in calculating 
the pure-rotenone content of s.. sample, unless particular accuracy v;as re- 
auired. 'tie also suggested the. use of optical rotation to determine the 
purity of the solvate, stating that the carbon tetracaloride present had 
no effect on the rotation. Results by this method v;cre slightly higher 
than by alcohol treatment. The amo-unt of rotenone left uncrystallized in 
the resin was not great, as saown by cooling and by adding further large 
amounts of rotenone and crystallising. Addition of 5 percent of cnarcoal 
to Derris root before extraction gave a lighter colored extract and a 
slight but definite increase in the purity of the solvate. Similar results 
were obtained when 10 percent of chercoal v;as added to i'undulea bark before 
extraction. The following is a condensed description of the method pro- 
posed by V/orsley: 
Sufficient air-dried, ground material is taken to give about 
1 gm. of rotenone, and 5 percent by weight of decolori2ing charcoal 
is added for Derr is or 10 percent for Mundulea. The mixture is run 
into the percolation tube, which is placed in the constant-tempera- 
txire bath, maintained at a few degrees below the boJling Doint 
of ethyl acetate, and the lower end is fitted to a 'liter flask. 
Suction is applied by means of a water pump. The cs.lculated amount 
of ethyl acetate is tnen neated almost to boiling mid is poured 
into tne top of the percolation tube. The smount required is 
approximately 20 cc. per gram when 10 \.o 20 gm. of material are 
used, 15 cc. per gram for 25 to 40 gr: . ., 500 cc. for 50 gm., and 
600 cc. for 100 {m. of material. Ay -joon as ta^^^ solvent appears 
at the bottom of t^.e tube, suction is adjusted so that the rate 
of percolation is about 2 drops per second; when slightly more 
tnan half the solvent has come through, it is inci'eased to about 
4 drops a second; and finally, when practically a.li the solvent 
is througn, full suction is applied. 
The extract is filtered into a distillin.?- flasi" ar^d prac- 
tically all the eth:/^l acetate distilled off. The resins are 
transferred to a small, v/eighed leaker, and the ethyl acetate 
is removed on tne water catn. The beaker is weighed to deter'nine 
the amount of resins. Sufficient ourifieri rotenone (40-mesn) is 
then added to bring th^ rotenone content in the resins up to at 
least 40 oercent; in any case at least 1.0 gm. is added. It 
is stirred into the heated resins on a water bath, 2 cc. of 
