366 



Journal of Agricultural Research 



Vol. X, No. 7 



evaporate. After a certain period, varying according to the volatility 

 of the compound, the solid was weighed again, the loss in weight being 

 the amount evaporated in that period of time. These data were then 

 reduced to gram-molecules evaporated in 400 minutes. 



The insect used in the tests was the housefly (Musca domestica L.), 

 reared under natural conditions. 



CHEMICALS TESTED 



In the selection of the organic compounds to be tested the object was 

 to obtain a series differing widely in their chemical composition and 

 toxicology. Their possible use as insecticides was not considered, 

 since the object of the investigation was to discover the general laws of 

 toxicity of volatile organic compounds to insects. 



The chemicals might be conveniently divided into hydrocarbons, 

 esters, acids, ethers, hydrocarbon derivatives containing hydroxyls, 

 aldehydes, ketones, halogens, sulphur or nitrogen, terpenes or terpene 

 derivatives, and alkaloids. The following list is thus divided : 



Hydrocarbons : 



Petroleum ether (pentane and hex- 

 ane). 



Gasoline (mostly heptane). 



Kerosene (mostly nonane and de- 

 cane). 



Benzene. 



Toluene. 



Xylene. 



Naphthalene. 



Camphene. 

 Acids: 



Acetic acid. 



Butyric acid. 



Valeric acid. 

 Aldehydes and ketones: 



Acetone. 



Acetaldehyde. 



Chloral hydrate. 



Brommethy Ipheny Iketone . 



Furfural. 



Menthone. 

 Sulphurs: 



Carbon bisulphid. 



Ethyl mercaptan. 



Allyl isosulphocyanate. 



Thiophene. 

 Terpenes and their derivatives: 



Camphene. 



Camphor. 



Menthone. 



Menthol. 



Pinene. 



Terpinol. 



Citral. 



Terpenes and their derivatives — Contd. 



Eugenol. 



Isoeugenol. 



Geranyl acetate. 

 Esters: 



Methyl salicylate. 



Ethyl malonate. 



Ethyl acetoacetate. 



Amyl acetate. 



Amyl valerate. 



Propyl acetate. 

 Ethers: 



Ethyl ether. 



a-Naphthol ethyl ether. 

 Hydroxyls: 



Methyl alcohol. 



Ethyl alcohol. 



Amyl alcohol. 



Menthol. 



Thymol. 

 Halogens: 



Chloroform. 



Bromoform. 



Carbon tetrachlorid. 



Chloretone. 



Brometone. 



Ethylene bromid. 

 Nitrogen : 



Chlorpicrin. 



Amyl nitrite. 



Nitrobenzene. 



Pyridin. 

 Alkaloids: 



Nicotin. 



