CHAPTER I. 



Insecticides. 



The results obtained from the use of any insecticide or fun^- 

 cide depend upon the operator. Timeliness, thoroughness and jjer. 

 sistence are the watchwords of success. It is easier to keep 

 an enemy away than to drive him away. The worst foes are 

 often the smallest ones, and the injury is often done before they 

 are detected. Be readj^ and begin early. 



Arsenic. — Kaiown to chemists as arsenious acid or white oxide 

 of arsenic. It is considered an unsafe insecticide, as its 

 color allows it to be mistaken for other substances ; but in 

 its various compounds it forms our best insecticides. From 

 1 to 2 grains usually prove fatal to an adult ; 30 grains will 

 usually kill a horse, 10 a cow and 1 gi^ain or less is usually 

 fatal to a dog. In case of poisoning, while awaiting the 

 arrival of a physician, give emetics, and after free vomiting, 

 give milk and eggs. Sugar and magnesia in milk is useful. 

 Araenites.— Compounds of arsenic, in which arsenious acid unites 

 with some metallic base. The leading arsenites used in 

 destroying insects are Paris gi'een and London purple : 

 Paris green. — An aceto-arsenite of copper. When pure, it 

 contains about 58 per cent, of arsenic, but the commercial 

 article usually contains less, often as little as 30 per cent. 

 The following may be considered an average analysis: 

 Arsenic, 47.68 per cent. ; copper oxide, 27.47 ; sulphuric acid, 

 7.16; moisture, 1.35; insoluble residue, 2.34. It is applied 

 in either a wet or dry condition, but in any case it must be 

 much diluted. For making a dry mixture, plaster, flour, 

 air-slaked lime, road dust, or sifted wood-ashes may be used. 

 The strength of the mixture required depends upon the 

 plants and insects to which it is to be applied. The strongest 

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