[Infection as indicator of finding complex environmental noxious agents within a short time (author's transl)]

We do not know whether complexes of chemical agents produce an accumulation of their respective noxious effects or whether these effects weaken each other and we have no exact methods to quantify these effects. Knowledge of such methods would be important for investigation of environmental health. In the course of researches how to influence infectious diseases by altering natural resistance we have found that it might be possible to use an indicator method: Animals exposed to such a light environmental toxic influence that they seem to be in a good health have a reduced period of survival time and an altered steroid metabolism after infection. The time of survival (after infection) and the steroid metabolism are the indicators of some hidden trouble caused by environmental influence. Here are three examples: 1) The covered intoxication with exhaust fumes, 2) the covered intoxication with lead salt and 3) the covered intoxication with DDT demonstrate the applicability of this method, results being available within a period of 2--3 weeks.