178 EXPERIMENT STATION. [Jan. 



The substances formerly employed as insecticides were 

 usually characterized by offensive or caustic rather than poi- 

 sonous properties. An acrid or bitter taste and a pungent odor 

 were evidently deemed necessary qualifications for insecticides, 

 and the more unpleasant the greater merit they were supposed 

 to possess. Among the more prominent, enumerated by early 

 writers,^ might be mentioned water, hot water, brine, urine, lye, 

 lime water, whitewash, clay wash, soapsuds, vinegar, petroleum, 

 tar infusion, turpentine, fish oil, whale oil, sulfur, decoctions of 

 aloes, dwarf elder, pejDper, quassia chips, rue, tobacco, walnut 

 leaves, wormwood and dustings of wood ashes, quick lime, soot, 

 sulfur, hellebore and tobacco. It is not surprising that the use 

 of such repellants (as a class they could not be designated other- 

 wise) was often ineffectual. The farmers were hampered fur- 

 ther by a very imperfect knowledge of the life history and 

 habits of the insects to be combated. To be sure, some of the 

 materials had insecticidal value, largely, however, as contact - 

 rather than as internal poisons, effective as an irritant, also, by 

 penetrating the cuticle or entering the body tissue through 

 breathing pores, and possibly in some cases by closing the 

 tracheae,^ resulting in the asphyxiation of the insect. The 

 application of these substances, singly or several together, con- 

 stituted the best recognized treatment both in this country and 

 abroad previous to 1860-70. 



Several materials deserve especial notice not only because they 

 possess merit, maintaining a place even to the present time, but 

 more particularly on account of the part taken in the develop- 

 ment of modern practice. These are hellebore, pyrethrum, kero- 

 sene and lime-sulfur. Hellebore, though known to possess 

 poisonous properties, received little attention until about 1842 

 in England ^ and later in this country.^ Pyrethrum has been a 



• Wm. Speechly, A Treatiseonthe Culture of the Pine-Apple (1779); J. A. E. Goeze, Geschiehte 

 einiffcr schadlichen Insecten (Leipzig, 1787). Cited by E. G. Lodeman, The Spraying of Plants, 

 p. 5, (1902); Samuel Doane, The Newengland Farmer or Georgical Dictionary, 2d edition (1797); 

 Wm. Forsyth, A Treatise on the Culture and Management of Fruit Trees (1802); Jas. Thatcher, 

 The American Orchardist (1822); Thos. G. Fessenden, The New American Gardener, 6th edition 

 (1832); Wm. Kenrick, The New .\merican Orchardist (1833); Thos. Bridgeman, The Young Gar- 

 dener's Assistant (1857); J. C. Loudon, The Encyclopedia of Gardening (1878). 



2 How Contact Poisons Kill, Geo. D. Shafer, Mich. Exp. Sta. Tech., Bui. No. 11 (1911). 

 ' No attempt was made to differentiate tracheal poisons from contact poisons in general. 



* A. Mitchell in Card. Chron., 1842, p. 397. 



■^ J. Harris in Country Gentleman, 1805, p. 413. 



