Order, control, the maintenance of established values and organizational relationships; these are central priorities for any social system. Any deviation from a given social order tends to be viewed as threatening or "polluting" — subject to what Mary Douglas has called "pollution behavior… a reaction which condemns any object or idea likely to confuse or contradict cherished classifications' (1). Science has been increasingly faced with many such external threats. Despite the emphasis on the tentative nature of all classifications and the importance of continued testing of scientific theories against new empirical criteria, scientists also find themselves engaged in pollution behavior to protect themselves against dangerous intrusions.