Remedial Measures and Insecticides. 



XXXI 



in purity of the chemicals. Mr. Lounsbury was working with 

 cyanide of 98 to 100 per cent, purity, while Mr. Coquillet was 

 using cyanide of only 33 to 58 per cent. It is therefore important 

 to know the exact amount of pure potassium cyanide in the 

 particular brand employed. 



The gas treatment has been largely used in combating scale 

 insects (particularly Aspidiotus atirantii) on orange trees. It will 

 be found the most effectual method for exterminating Orthezia 

 insignis, or any other insect, upon individual trees. 



Soap and Soapy Emulsions. 

 Soap by itself has considerable insecticidal properties. In fact, 

 in many popular mixtures, it is extremely probable that the soap is 

 the most efficacious ingredient. It acts by asphixiation, forming 

 an impervious film over the breathing pores of the insects. 



