57 .. 
mlnation of rcten.one in aq-j^iouf? extracts of derris, ji.nd this use of the 
procedure was describ'^d in det.-i.il. 
Gstirner (5l) in 1934 emp] o/ed the method of Dnnckvortt and covrorkers 
in the anal;ysi5 of 19 sniiiples ar.d fractions of sanples of derria root. 
In all cases e:ccept on© results ivere higher than those by crystallization, 
in most casus jnarkedly hjguor. This diffe-^tnce was attributed to the 
rotenone remaining in tiio. rosin from t.hs crystallization. 
Lanckv/ortt' B m'^thod -ms also us^d by Fischer and Titcche (28) in 1935 
in a study of chemical methods for the evaluation of commercial derris 
preparations. These Investigators found, that extraction of the sample for 
this jjurposewas comolete in 3 to 4 hours. In certain cases it was 
necessary to have more derris resin prec-sont than specified by lanckvortt 
and coworkers. 
Rowann (l05) in 1935 report''-^d that in analyse'? of samples of derris 
root the rotenone coxitent vsras usually highor by the polarimetric method 
of Danckwortt and his cov/orkers tV.an by crystallisation, but that in two 
samples the values by crystallization were abort double tncse by the optical- 
rotation method. Eo-^aan also reported the isolation of a dextrorotatory 
preparation of toxicarol from derris. because of these circumstances 
analysts were warned against the use of the polarimetric method. 
In reply Danckwortt (.2Z) pointed out that the polari-^etric method 
Was. a means of determining tiie effective value of derri? and not of deter- 
mining rotenone. Ee also reported the use of the method in a study of the 
relative strbillty of inductrial derris extracts ever a. piriod of time. 
The extracts wore dried V'ith smd, the residue was shairen vdth benzene for 
20 minutes, ana the optical rotation of the solution was ifttermined as 
previously described. Stror^gly colored solutions were shaken with animal 
charcoal. Too much ch^^rcoal was avoided, since it caused a decrease in 
optical activity. 
Rowaan (106) in 1936 again warned against the use of the polarimetric 
method for the determination of rotenone in derris rnd stated that the 
most reliable method was soma modification of the extraction-crystallization 
method, 
Tattersfield and Martin (i;23.) in 1S36 studied the optical activity of 
benzene solutions of resiis and v,heir fractions derived from samples of 
Der ris elliptic a. D. roalac ^ ccnsis , and Sumatr-'^-t^/pe derris root. A fraction 
of Sumatra-type fesin obtained oy means of methyl alcohol was dextrorotatory 
in methyl alcohol but levorotatory in benzene, 
A sttidy of the optical rotatory povr~r of acetone and benzone extracts 
of 15 saonples of derris and 10 samples of cube root was reported by Jones 
(65) in 1936. Calculations of hj-pothetical rotenene contents wore based on 
the kr.own rotations of pure rotenone in acetone and bonzene, as was done 
in earlier work (62). All extracts were levorotatory in benzene, but 
