78 BULLETIN" 824, U. S. DEPARTMENT OF AGRICULTURE. 



the material. That saponification with alcohoUc potash effects chem- 

 ical decomposition in some of the compounds present is also shown 

 by the fact that petroleum ether added to the U. S. P. ether solution 

 of the saponifiable portion precipitates a resin, whereas all the mate- 

 rial before saponification was soluble in petroleum ether. 



Procedure 2. 



Since saponification with alcoholic potash destroys the insecticidal 

 action of the material extracted by petroleum ether, another proce- 

 dure was adopted. A petroleum-ether extract was obtained as be- 

 fore, evaported to dryness, and taken up in U. S. P. ether. This 

 ethereal solution was successively extracted with aqueous solutions 

 of ammonium carbonate, sodium carbonate, and sodium hydroxid, 

 made up on the basis of 10 grams of salt to 100 cc. of solution. The 

 ammonium carbonate solution assumed a light yellow color when 

 shaken with the ethereal solution of the extract. Emulsions which 

 were difficult to separate formed. After repeatedly extracting with 

 ammonium carbonate and washing with water, the ethereal solution 

 was separated, and reserved for the sodium carbonate extraction. 



The ammonium carbonate solution was made acid with sulphuric 

 acid and shaken with ether, which slowly and apparently incom- 

 pletely took out the yellow color. On evaporatmg this ether extract 

 to dryness, after washing and drying over calcium chlorid, a few 

 greenish-yellow, oily, sticky drops were left. From 1,920 grams of 

 powdered flowers only 0.345 gram of material was thus obtained. 

 This amount was too small for purification and chemical testing, and 

 was, therefore, used for testing on insects. It was dissolved in about 

 50 cc. of 95 per cent alcohol, diluted with an equal quantity of water, 

 and sprayed on nasturtium plants which were infested with aphides. 

 From 75 to 80 per cent of the aphides were killed. In check tests 

 with 50 per cent alcohol no aphides were killed. 



The aqueous solution of sodium carbonate removed a noticeable 

 amount of a brownish-yellow material, which was obtained as a 

 sticky mass after acidifying and extracting with ether. Tested 

 against aphides in the same way, the material proved to be very ac- 

 tive, killing 100 per cent. Extraction with sodium hydroxid solu- 

 tion removed a quantity of chlorophyll and also some of the insec- 

 ticidal constituents. About 80 per cent of the aphides sprayed with 

 an aqueous alcoholic emulsion of the extracted material were killed. 

 On evaporating the ethereal solution of the original petroleum-ether 

 extract after these successive extractions with aqueous ammonium, 

 carbonate, sodium carbonate, and sodiumi hydroxid, a strong reddish- 

 orange pasty material was left. Tested on aphides, this miaterial 

 likewise exhibited marked insecticidal power, killing about 90 per 

 cent of the insects. 



