To the Editor:—
In The Journal (Oct. 29, 1960, p. 1200) the author writing concerning fatal anaphylactic shock following an intradermal skin test with horse serum tetanus antitoxin stated that a "skin test dose of 0.1 cc. horse serum tetanus antitoxin in 1:10 dilution with isotonic sodium chloride solution was given intradermally." Later he states that "the intradermal test should be given initially with a dilution no stronger than 1:100." It should be pointed out also that the proper skin test dose is approximately 0:01 cc. when testing for the immediate type of allergy, which is the purpose of the horse serum test. Larger doses are not necessary and increase the hazard of the skin test. The volume necessary for this type of skin test is distinctly smaller than that commonly used for a delayed type of antibody, such as the one involved in the commonly used tuberculin-type skin test.