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444 young creatures are guided by their elders, would also contribute to achieve the same outcome. The chief corollary of this principle is found in the theory of pleasure-pain factors acting upon the accommodatory movements of adaptation. Mr. Baldwin's formula runs somewhat as follows: Painful stimulations produce movements of retraction and restriction; pleasurable stimulations, on the other hand, occasion profuse expansive movements. Out of the matrix of over-produced movements brought about by pleasurable stimuli, the organism selects the particular co-ordinations relevant to the special situation to be met. These movements persist rather than others primarily because they are agreeable, and because all such reactions tend by virtue of the very constitution of the organism to reinstate themselves, so long as they are agreeable.

Stated in its most general form, 'organic' selection, as Mr. Baldwin calls his active principle, appears to offer an exceedingly sensible and plausible account of one stage in the operation of natural selection. It thus becomes a subordinate chapter in the whole statement of evolutionary process from the natural selection point of view. It contains a more precise description of the early stages in the acquirement of modifications (ontogenetic) and variations (phylogenetic, congenital) than had before been clearly articulated. For those who accept the genuineness of sexual selection, organic selection must constitute a similar but more general category, inasmuch as it involves consciousness in all of its directions of expression, whereas sexual selection involves only one of its modes of activity. Such a theory seems almost truistic once it is propounded, and yet it is undoubtedly of conspicuous value in unifying the discrepant forms of interpretation advanced by different biologists for certain groups of facts. To the Lamarckian who bases his faith either upon alleged instances of inheritance of acquired characteristics, or upon the asserted impossibility of explaining by the destructive action of natural selection the evolution of structures and functions which were useless up to the time of their complete development, the theory offers an alternative hypothesis showing how the semblance of transmission of acquired characters may arise from the cumulation of modifications in organisms whose adaptive reactions enabled them to live and beget offspring during the period in which these modifications (originally useless, perhaps) were becoming established. To the Darwinian, on the other hand, who has been wont to lay all the stress upon the controling influence of natural selection in weeding out the unfit, such a theory invites a redistribution of emphasis, by exhibiting the primary