IT IS NOTEWORTHY that in spite of the almost worldwide use of DDT (2,2-bis[p-chlorophenyl] 1, 1, 1-trichlorethane) very few untoward reactions caused by it have been reported. Even during the Italian campaign in December 1943 and January 1944, when it was used extensively on all the troops of the United States Army for the destruction of body lice to control a louse-born typhus epidemic in Naples, not only was the measure so effective that not 1 case of typhus occurred in an American soldier but as a matter of fact and consternation there was no mishap or unpleasant reaction.1 To evaluate subclinical manifestations of possible poisonous effects Case2 undertook an ingenious study. He placed 2 volunteer men in contact, for two forty-eight hour periods, with the walls of a chamber coated with a film containing 2 per cent DDT by weight and