Judged from our present standpoint, the most valuable feature of Sidis’s book is that it calls attention to the undoubtedly intimate relation between gregariousness and suggestibility. The mechanism, however, by which he supposes suggestibility to come into action is more open to criticism. The conception of a permanent subconscious self is one to which it is doubtful whether the evidence compels assent.[K] The essential difference, however, which Sidis’s views present from those to be developed below, lies in his regarding suggestibility as being something which is liable to intrude upon the normal mind as the result of a disaggregation of consciousness, instead of as a necessary quality of every normal mind, continually present, and an inalienable accompaniment of human thought. A careful reading of his book gives a very clear impression that he looks upon suggestibility as a {28} disreputable and disastrous legacy of the brute and the savage, undesirable in civilized life, opposed to the satisfactory development of the normal individuality, and certainly in no way associated at its origin with a quality so valuable as altruism. Moreover, one gets the impression that he regards suggestibility as being manifested chiefly, if not solely, in crowds, in panics, revivals, and in conditions generally in which the element of close association is well marked. [K] In this connexion the “Symposium on the Subconscious” in the _Journal of Abnormal Psychology_, vol. ii. Nos. 1 and 2, is of much interest. The discussion is contributed to by Münsterberg, Ribot Jastrow, Pierre Janet, and Morton Prince. (_b_) Deductive Considerations The functions of the gregarious habit in a species may broadly be defined as offensive or defensive, or both. Whichever of these modes it has assumed in the animal under consideration, it will be correlated with effects which will be divisible into two classes—the general characteristics of the social animal, and the special characteristics of the form of social habit possessed by the given animal. The dog and the sheep illustrate well the characteristics of the two simple forms of gregariousness—offensive and defensive. 1. _Special Characteristics of the Gregarious Animal._ These need not be dealt with here, as they are the qualities which for the most part have been treated of by psychologists in such work as has been done on the corollaries of gregariousness in man. This is because they are qualities which are most evident in man’s behaviour when he acts in crowds, and are then evident as something temporarily superadded to the possibilities of the isolated individual. Hence it has come about that they have been taken for the most part as constituting the whole of man’s gregarious inheritance, while the possibility that that inheritance might have {29} equally important consequences for the individual has been relatively neglected. 2. _General Characteristics of the Gregarious Animal._