Biological activity unrelated to structure. Ferguson’s Principle

Abstract

As has been abundantly shown in the last eight chapters, most biologically active substances are extremely sensitive to small changes in structure (see, for example, the introduction to Chapter 7). However, no such correlation exists for one class of substance: the biological depressants. These are the substances used as hypnotics and general anaesthetics. High concentrations of depressants are also used as volatile insecticides, particularly in the fumigation of stored grain. The antimitotic effects mentioned in Section 15.1 are also evident at low concentrations and seem to be independent of structure.