72 DDT — Killer of Killers 



type. With standards of performance set up, the various 

 manufacturers would have a common basis for comparing 

 the qualities of their different products, and each manufactu- 

 rer who desired could then indicate on his labels how his 

 insecticide stacked up with the others. 



On September 20, 1937, the National Association of 

 Insecticide and Disinfectant Manufacturers, Inc. proposed 

 the establishment of a commercial standard for household in- 

 secticides of the liquid-spray type; and the standard was later 

 accepted and approved for promulgation by the U. S. Depart- 

 ment of Commerce, through the National Bureau of Stand- 

 ards. This standard — known as G)mmercial Standard 

 CS72-38 — became effeaive on June 10, 1938. If you are 

 interested, the Superintendent of Documents, Washington, 

 D. C, will sell you a copy for 5 cents. 



An inseaicide that meets the requirements of the stand- 

 ard must be harmless to man and warm-blooded household 

 animals when used as direaed; it must not stain household 

 furnishings, wall paper, etc.; it must not corrode metals; and 

 it must have no objectionable odor. But the most important 

 of the specifications deals with performance. And the only 

 way you can tell what an inseaicide will do is to try it out 

 on insects. 



For determining the killing power of a liquid insecti- 

 cide, the Peet-Grady method has been accepted as the stand- 

 ard. In this method, approximately 100 houseflies, not 

 less than 3 nor more than 5 days old, are placed inside of a 

 test chamber, which is a 6-foot cube, constructed of wood or 

 metal, and lined so that the inner surface is smooth, relative- 

 ly nonporous, and free of cracks, projections, etc. The cham- 

 ber is provided with a large, tight-fitting door, windows for 



