circumstances of their formation were so unusual as to keep them out of ordinary associational remembrance. Thus a remarkable case is mentioned by Dr. Abercombie ("Intellectual Powers," fifth edition, p. 149) of a boy, who, at the age of four years, underwent the operation of trepanning, apparently in a state of perfect stupor, and who, after his recovery, retained no recollection either of the accident by which his skull was fractured, or of the operation, yet who, at the age of fifteen, during the delirium of fever, gave his mother an account of the operation and of the persons who were present at it, with a correct description of their dress, and other minute particulars of which it was scarcely possible that he could have acquired the knowledge from verbal information. Here it would seem that all the Mental power the patient then had must have been concentrated upon the impressions made upon his Sensorium, which were thus indelibly branded (as it were) upon his Organism; but that these "traces," being soon covered up by those resulting from the new experiences of restored activity, remained outside the "sphere of consciousness" until revived by a Physical change which reproduced the images of the objects that had left them.
The direct causal relation of Physical conditions to Mental states may be made still more clear by following out into some detail the phenomena of that peculiar form of Intoxication which is produced by Hashish—a preparation of Indian hemp used in the Levant for the purpose of inducing what is termed the fantasia. The action of this drug was very carefully studied some years ago by M. Moreau, Physician to the Bicetre, who had given great attention to the Psychology of Insanity, and whose special object was to throw light upon that subject by experimenting upon what he termed its artificial production. His treatise, "Du Hachisch, et de l'Aliénation Mentale" (Paris, 1845), is one which deserves the attentive study of such as desire to base their Psychology upon a comprehensive survey of facts.
One of the first appreciable effects of the Hashish, as of other Intoxicating agents, is the gradual weakening of that power of Volitionally controlling and directing the current of thought, the possession of which characterizes the vigorous mind. The individual feels himself incapable of fixing his attention upon any subject; the continuity of his thoughts being continually drawn off by a succession of disconnected ideas, which force themselves (as it were) into his mind, without his being able in the least to trace their origin. These speedily engross his attention, and present themselves in strange combinations, so as to produce the most impossible and fantastic creations. By a strong effort of the Will, however, the original thread of the ideas may still be recovered, and the interlopers may be driven away; their remembrance, however, being preserved, like that of a dream recalling events long since past. These lucid intervals progressively become shorter in
