258 SUCCESSFUL FARMING 



dwellings, and is sometimes found with an arsenite as an ingredient of 

 proprietary roach pastes. Recent work done with a view to destroying 

 the larvae of house flies in manure indicates that this is one of the best of 

 insecticides for the purpose, excelling for this use, coal oil, pyroligneus acid, 

 formalin and Paris green. Sodium borate and crude calcium borate were 

 both found effective in killing the larvae, either when used dry or in solu- 

 tion. It was recommended as a result of the work done that about 0.62 

 pound of borax be used in 8 bushels of manure. Larger amounts of borax 

 are believed to be injurious to plants when the manure is spread on land. 

 The cost was estimated at one cent per horse per day. 



Other Insecticides. Numerous other insecticides have been recom- 

 mended, and have had a limited use, but, excepting the fumigants con- 

 sidered later, they have not been generally adopted by practical men. 

 Among them may be mentioned benzene, which is sometimes applied to 

 fabrics to destroy clothes moth; carbolized plaster, sometimes recom- 

 mended as a remedy for fleas about stables; fir-tree oil, lemon oil and oil 

 of citronella, the latter often employed as a deterrent against the attacks 

 of mosquitoes and also as a preventive of injury to seed corn in the soil. 

 Quassia, the effective ingredient of which is quassiin, is obtained from 

 the wood of the Jamaican Picrasma excelsa. It is an old insecticide that 

 has been perhaps most used in solutions for the hop aphis in the West. 

 The extract is made from the " chips" by either soaking or boiling. 



Bisulphide of Carbon. As sold by druggists and manufacturers, this 

 is a brownish fluid which quickly disappears in the air when exposed in 

 an open vessel. Its disagreeable odor is due to impurities, since the odor 

 of pure bisulphide of carbon is not unpleasant. The fumes are not only 

 poisonous, but are inflammable, so that some care must be exercised in 

 handling the fluid. It has proved of special service as a remedy for grain 

 weevil, bean weevil and other insects attacking stored seeds, and for the 

 phylloxera of grapevines in Europe, for the woolly aphis, for ants, and 

 even for the clothes moth. Its great value for such purposes comes not 

 only from its effectiveness in destroying all insects, but also because it is 

 not corrosive and is otherwise not injurious to seeds, fabrics and other 

 objects fumigated. The offensive odor is soon gone if objects that have 

 been exposed to the fumes are thoroughly aired. It cannot be used for 

 fumigating plants infested with insects because of its destructive effect on 

 the plants themselves. 



About one fluid ounce should be used on each bushel of seed, and may 

 be poured over the seeds or simply placed in a saucer or other open vessel 

 set on their surface. It is absolutely necessary that the seeds be enclosed 

 in a tight box or bin to get satisfactory results, and the time of exposure 

 should not be less than two nours. 



Carbon Tetrachlorid. The disagreeable o$or O f commercial bisulphide 

 of carbon renders it objectionable to some people for use on fabrics infested 

 with moth, and has led to the suggestion that carbon tetrachlorid, which 



