groups; while the rational realm maybe defined as that arising with the accession of reason as a guide to action, and with the development of nature-conquest as its most characteristic effect—though it is to be noted that the several transitions are progressive rather than saltatory. Thus each realm is characterized by the attributes of each and all of those lower in the scale, plus its own distinctive attribute. It may also be pointed out that each new attribute defining a higher realm is freer and more spontaneous than those of lower realms; for vitality is freer than mere affinity, self-movement than mere growth, and cooperation than mere movement, while reason-led action is freest of all. Accordingly each realm (as already implied) is characterized by a larger autonomy than any of those lower in the scale; i. e., by all the factors of autonomy in the lower realms, plus its own distinctive factor. [264] Cf. American Anthropologist, new series, vol. 1, 1899, p. 374. It may be pointed out farther that, in the higher realms at least, the action normal to each realm tends to generate that characteristic of the next higher realm: the self-movement of the animal realm is, under favorable conditions, constrained through vital economy to fall into the conjustment of the social realm; and the organization of the social realm, involving as it does a hierarchic arrangement of organisms according to mentality,[265] habituates the higher individuals of the organizations to that control of lower individuals which buds in agriculture, blossoms in civil rule, and fruits in nature-conquest. Thus the factors of each realm are prophetic of the distinctive factor of the next higher—and the prophecy is not merely passive, but is, rather, an actual step in causal sequence. [265] The spontaneous arrangement of organisms in accordance with mental grade is well illustrated by that solidarity of desert life which matures in the cultivation of plants and the investigation of animals (The Beginning of Agriculture, in The American Anthropologist, vol. VIII, October, 1895, pp. 350-375; The Beginning of Zooculture, ibid., vol. X, July 1897, pp. 215-230.) It may be pointed out still further that, in the higher realms at least, spontaneous action necessarily precedes maturely developed function: in the vegetal realm the tree shoots upward before its form is shaped and its tissue textured by wind and sun and environing organisms; in the animal realm youthful play presages the prosaic performances normal to adult life; in the social realm men behave before framing laws of behavior; and in the rational realm fortuitous discovery paves the road for sure-footed invention. Thus natural initiative arises in spontaneous action, while mechanical action is mainly consequential.