4 BULLETIN 165, U. S. DEPARTMENT OF AGRICULTURE. 



In studying the use of quassiin as a contact insecticide it became 

 desirable to determine in what solvents and solutions this com- 

 pound was soluble. Table I gives the results of the experiments 

 which were carried out with this purpose in view. 



Table I. — Results of solubility tests for quassiin. 



No. 



Material. 



Action. 



1 

 2 

 3 

 4 

 5 

 6 

 7 

 8 

 9 

 10 

 11 





Readily soluble. 

 Not soluble. 

 Readily soluble. 



Do. 



Do. 

 Sparingly soluble 1-1,200. 

 Not soluble. 



Do. 



Do. 



Do. 

 Possibly soluble. 



Ether 























RESULTS OF TESTS WITH SOLUTIONS. 



12 

 13 

 14 

 15 

 16 

 17 

 18 

 19 

 20 

 21 

 22 

 23 

 24 



Potassium hydroxid 



Readily soluble, solution yellow. 



Do. 



Do. 



Do. 



Do. 



Do. 



Do. 



Do. 

 Apparently insoluble. 



Do. 



Do. 



Do. 



Do. 











Ammonium hydrate 



Whale-oil soap (alkaline) 













The foregoing table represents the results of experiments which 

 were conducted with quassiin in an attempt to determine some cheap 

 solvent or solution, other than hot water, by which it could be 

 extracted from the wood. 



EXTRACTION OF QUASSIIN FROM SOLUTIONS. 



It was found that when the solutions of potassium hydroxid, sodium 

 hydroxid, sodium carbonate, etc., with quasshn, were acidulated 

 with sulphuric acid, the quassiin could be readily removed in chloro- 

 form. This process would apply when testing the percentage of 

 quassiin in such solutions. 



DETERMINATION OF PURITY OF QUASSIIN USED. 



Since the purity of the quassiin used in spraying experiments is 

 an important factor in figuring proportions, an attempt was made to 

 determine the amounts of material other than quassiin which might 

 be present in the stock solution. 



Following a suggestion in Allen, tannin was added to an aqueous 

 solution of quassiin taken from the stock solution. A fine precipitate 

 appeared, but unfortunately it passed through an ordinary filter 

 paper. 



