Aug. IS, I9I9 D err is as an Insecticide 185 



dissolved in boiling alcohol, and then the solution was heated with animal 

 charcoal and filtered. Upon evaporation, the resin closely resembled the 

 appearance it had before being treated with the charcoal and seemed to 

 consist of two forms, the greater portion being of a soft and pliable nature, 

 while the other portion was hard and brittle. The latter had a melting 

 point of 66°-68° C. Van Sillevoldt reports the melting point of "derrid" 

 as being about 73° C. 



Two gm. of the soft portion were dissolved in 50 cc. of 95 per cent alcohol 

 by means of a low heat ; upon standing, a fine, yellowish-white powder 

 settled to the bottom of the flask; then this powder was separated by 

 means of a force filter, and after being washed with a small quantity of 

 alcohol and ether it was dried. This material appeared like an amorphous 

 powder, but under the microscope it was found to consist of small plate- 

 like crystals. The melting point of these crystals was 170° C. 



A dilute alcoholic solution of the above crystals, as well as the alcoholic 

 solution of the resin from which the crystals had been separated, was 

 found to be very toxic to fish. A subcutaneous injection of 0.00066 gm. 

 of the crystals was fatal to a mouse in two hours. 



The preceding method of extracting the resin is not very practicable 



on a large scale. Several of the operations involved could possibly be 



dispensed with. 



power's method 



One kilo of the powdered root of Derris sp. was repeatedly extracted 

 with boiling alcohol until exhausted. Upon removal of the alcohol by 

 distillation under reduced pressure, 173 gm. of a dark extract of a pillular 

 consistency were obtained; this amount is equivalent to 17.3 per cent of 

 the dry root. Then the extract was repeatedly extracted under a reflux 

 condenser with hot petroleum ether until the latter was no longer 

 colored. From the combined extracts the petroleum ether was removed 

 and a waxy, yellow residue weighing 16 gm. remained. This residue was 

 designated A . 



The alcoholic extract after having been exhausted with petroleum ether 

 was heated on a steam bath with 95 per cent alcohol until it was brought 

 into solution, whereupon it was poured slowly into a large quantity of cold 

 water; a fine suspended precipitate resulted. The precipitated resin 

 was filtered by means of a force filter, then washed with water, dried by 

 means of an electric fan, and finally pulverized to a No. 20 powder which 

 was grayish in color and weighed 102 gm., being equivalent to 10.2 per 

 cent of the original material. This was designated B. 



Sixty-five gm. of the resin B were extracted in a Soxhlet extractor with 

 chloroform until exhausted; 11.4 gm. or 17.5 per cent remained undis 

 solved. This portion was removed from the extractor, was dissolved in 

 alcohol, and then precipitated in cold water. After the precipitate had 



