An epidemiologic study of Q fever, as made in the endemic area of southern California, suggests three modes in which the infection may be spread: (a) occupation in dairy or livestock industries, (b) use of raw milk and (c) residence within 1/4 mile of places where cattle are maintained or beef is processed.1It has been estimated that more than 10 per cent of the cattle in this region are infected with Coxiella burnetii, the etiologic agent of Q fever, and that more than 50 per cent of the raw milk produced in this area is infective for guinea pigs.2Cases of Q fever have occurred among slaughterhouse workers3and laboratory technicians.4C. burnetii has been found in ticks,5and 1 case has been reported in which the infection was probably caused by the crushing of ticks between the fingers.6 It has been stated