‘All or None’: a Question of Nomenclature.

THE `all or nothing' hypothesis represents such a clear-cut principle in elementary physiology that it seems a pity that the ambiguous phrase, `all or none' should so often be used instead. We have been accustomed to suppose that a given physiological unit, or set of units, shows either `all or nothing' of the response it can make under given conditions; also that additions to this response, under the same conditions but with greater stimulus, can be made only by co-operation (or, in a special context, `recruitment') of additional units. This meaning is actually excluded by the nickname `all or none' because we have supposed that `some' units, few or many, fill in intervening stages of intensity of the response.