[Paul Ehrlich's methods for deciphering the immune defence. One method leads only to an incomplete understanding].
Paul Ehrlich's routes to decipher the immune defence came on the one side as a black box consideration from differences in the potency of the final result and on the other side from connections between the single events. In consequence of the assumption of linear interactions between the single events it was believed, as in the case of pharmacology, that Ehrlich's black box consideration from the final result could be dispensed with. The single event would be already representative for the proceedings in general. But the assumption is wrong and Ehrlich's black box consideration from the final result has to be applied again to decipher the real causes of sufficient or insufficient immune defences, of immune diseases, of allergies etc. We have to learn again, how to use two contrary considerations, which likewise have their rights, to understand the immune defence.