The instinct of pugnacity was to be seen in many a fine example of difficulty overcome in the work of rescue; as also in other instances, some suggestive of that early combat when animals and men struggled for mere physical existence. The parental instinct was everywhere in evidence, and was reflected not only in the sacrifices made and the privations endured by parents for their young, but in every act of relief, which arose in involuntary response to the cry of the distressed. It perhaps partially explains the phenomenon often noticed in disasters that "immediately and spontaneously neighbors and fellow-townsmen spring to the work of rescue and first aid."[51] [51] Deacon, J. Byron, _Disasters_ (N. Y., 1918), ch. vi, p. 151. The gregarious instinct--the instinct to herd--showed itself in the spontaneous groupings which came about and which seemed somehow to be associated with feelings of security from further harm. The refugees found comfort in the group. They rarely remained alone. These and other instinctive responses in a greater or less degree of complication were to be remarked of the actions not only of individuals but of groups as well. In the latter the typical phenomena of crowd psychology were manifested upon every hand. The crowd was seen to be what it is--"the like response of many to a socially inciting event or suggestion such as sudden danger." Out of a mere agglomeration of individuals and under the stress of emotional excitement there arose that mental unity, which Le Bon emphasizes.[52] There was noticeable the feeling of safety associated with togetherness which Trotter suggests.[53] There was the suggestibility, with its preceding conditions which Sidis[54] has clarified, namely, expectancy, inhibition, and limitation of the field of consciousness. There were the triple characteristics which Giddings notes: "Crowds are subject to swift contagion of feeling, they are sensitive to suggestion .... and always manifest a tendency to carry suggested ideas immediately into action."[55] [52] Le Bon, _op. cit._, p. 26. [53] Trotter, William, _Instincts of the Herd in Peace and War_ (London, 1919), p. 31. [54] Sidis, Boris, _The Psychology of Suggestion_ (N. Y., 1919), ch. vi, p. 56 _et seq._ [55] Giddings, Franklin H., _Principles of Sociology_ (N. Y., 1916), bk. ii, ch. ii, p. 136. Of illustrations of impulsive social action there are none more apt than those furnished by the reactions following the Halifax tragedy. Only Pliny's narrative of the flight from the eruption of Vesuvius, or the story of the "Day of Fear" in France,[56] or that depicting the days of the comet[57] are comparable thereto. [56] Stephens, Henry M., _A History of the French Revolution_ (N. Y., 1886), vol. i, p. 179. [57] Wells, H. G., _In the Days of the Comet_ (N. Y., 1906).