[7] It is of course only as physiological traits that the tropisms are conceived not to overlap, blend or interfere, and it is likewise only in respect of their physiological discontinuity that the like argument would bear on the instincts. In respect of their expression, in the way of orientation, movement, growth, secretion, and the like, the tropismatic response to dissimilar stimuli is often so apparently identical that expert investigators have at times been at a loss to decide to which one of two or several recognised tropismatic sensibilities a given motor response should be ascribed. But in respect of their ultimate physiological character, the intimate physiological process by which the given sensibility takes effect, the response due to different tropismatic sensibilities appears in each case to be distinctive and not to blend with any other response to a different stimulus, with which it may happen to synchronise. [8] Cf., e. g., McDougall, _Introduction to Social Psychology_, ch. i-iii. [9] Cf., e. g., Otto Ammon, _Die Gesellschaftsordnung_; G. Vacher de Lapouge, _Les sélections sociales_, and _Race et milieu social_, especially “Lois fondamentales de l’Anthroposociologie.” [10] The all-pervading modern institution of private property appears to have been of such an origin, having cumulatively grown out of the self-regarding bias of men in their oversight of the community’s material interests. [11] Cf. McDougall, _Social Psychology_, ch. x. [12] Latterly the question of instincts has been a subject of somewhat extensive discussion among students of animal behaviour, and throughout this discussion the argument has commonly been conducted on neurological, or at the most on physiological ground. This line of argument is well and lucidly presented in a volume recently published (_The Science of Human Behavior_, New York, 1913) by Mr. Maurice Parmalee. The book offers an incisive critical discussion of the Nature of Instinct (ch. xi) with a specific reference to the instinct of workmanship (p. 252). The discussion runs, faithfully and competently, on neurological ground and reaches the outcome to be expected in an endeavour to reduce instinct to neurological (or physiological) terms. As has commonly been true of similar endeavours, the outcome is essentially negative, in that “instinct” is not so much explained as explained away. The reason of this outcome is sufficiently evident; “instinct,” being not a neurological or physiological concept, is not statable in neurological or physiological terms. The instinct of workmanship no more than any other instinctive proclivity is an isolable, discrete neural function; which, however, does not touch the question of its status as a psychological element. The effect of such an analysis as is offered by Mr. Parmalee is not to give terminological precision to the concept of “instinct” in the sense assigned it in current usage, but to dispense with it; which is an untoward move