April 2, 1886.] 



SCIENCE. 



311 



explain them. There must be some modification 

 of the cerebral innervation, a receptivity and an 

 aptitude very different from those in the normal 

 state. 



A distinct and strong impression must be made 

 upon the somnambulist in order to command his 

 attention, — a nervous shock arresting the course 

 of his thoughts. This cerebral shock, if it may 

 be so expressed, seems to be the sine qua non of 

 success : it produces a sort of cerebral modifica- 

 tion, some particular unknown state, without 

 which impressions can have no effect. It is of 

 interest to inquire whether we do not find analo- 

 gous physiological or pathological states. There 

 would seem to be certain features of surgical 

 shock following severe operations, and causing 

 singular conditions of mental alienation, that are 

 similar ; and is there not also a resemblance shown 

 in the condition of deep mental abstraction wit- 

 nessed in some persons ? The characteristic trait 

 of all these different conditions is a momentary 

 suspension, more or less complete, of cerebral 

 activity. This suspension may present all varying 

 degrees, from the profound collapse following sur- 

 gical operation, to the simple mental distraction. 



THE NATURE OF SO-CALLED DOUBLE 

 CONSCIOUSNESS AND TRIPLE CON- 

 SCIOUSNESS. ■ 



There is a rather widely spread impression that 

 human beings can be subjects of double conscious- 

 ness, and can lead two separate lives, in each of 

 which the individual has a distinct set of personal 

 characteristics. Illustrations of this supposed 

 psychological possibility are found in many recent 

 works of fiction, notably in the 1 Archibald Mal- 

 maison ' of Julian Hawthorne, and « Called back ' 

 of Hugh Conway. Some medico-legal interest has 

 also been attached to the question in a number of 

 instances. Having had one case somewhat of this 

 character under observation, I have been led to 

 examine the matter critically. 



There are on record in French, German, Eng- 

 lish, and American medical literature only seven- 

 teen cases whose history in any way entitles them 

 to come under the designation of cases of double 

 consciousness. Most of them were reported from 

 forty to sixty years ago, and without very 

 great accuracy in detail. An examination of all 

 these histories, and the study of cases allied to 

 them, lead one very positively to the conclusion 

 that such a thing as a true double consciousness, 

 or dual life, does not exist. There are several 

 striking instances in which persons have lived an 

 apparently double life, but in each case the second 

 life represented simply a partial activity of the 



patient's brain. In the second and morbid state 

 a portion, viz., the higher volitional centres, have 

 their activity inhibited, the mind is dull, the 

 disposition apathetic, and memory of the past is 

 gone. Indeed, this loss of the faculty by which 

 stored-up impressions of the past are revivified is 

 the main psychological feature of some cases. 



In 1845 Dr. Skae reported the case of a lawyer, 

 of whom he said, "He appears to have a double 

 consciousness, a sort of twofold existence, one 

 half of which he spends in the rational and intelli- 

 gent discharge of his duties ; the other, in a state 

 of helpless hypochondriasis, almost amounting to 

 complete aberration." His attacks occurred every 

 other day. In the classical case reported by Azam, 

 the patient, in one mental state, was dull, apa- 

 thetic, and little better than an automaton, show- 

 ing here, again, that it was a condition in which 

 some of her mental faculties were suspended. A 

 Kentucky farmer twenty-three years old was acci- 

 dentally struck on the head with a hammer. He 

 was unconscious for several hours, but recovered, 

 and seemed as well as ever. He married, and 

 had children, but, after eight years, began to 

 show signs of insanity. He was trephined, and 

 his mental faculties were completely restored ; but 

 the whole eight years since the blow on his head 

 was a complete blank. He did not know his w r ife, 

 or children, or any of his later associates. This 

 was not so much a case of double consciousness, 

 though so reported, as of loss of memory. 



The theory that the two mental states corre- 

 spond with special activity of one side or the 

 other side of the brain, is not at all tenable, be- 

 cause, if for no other reason, one of the cerebral 

 hemispheres may be almost entirely destroyed, 

 or its connecting commissure may be injured or 

 absent without producing any such phenomenon 

 as double consciousness, or a change in person- 

 ality. Besides, there have been at least two cases 

 reported in which three different mental states 

 occurred. One of them was recently reported by 

 J. Voisin. A young man suffering from hysteria 

 major had an attack of amnesia, or loss of mem- 

 ory, lasting for a year : there was entire forgetful- 

 ness of his past, a change in his character and 

 demeanor. This state could be artificially changed 

 into a third state by hypnotizing him, after which 

 he would return to his second or abnormal state. 

 After being restored to his normal mind for a year, 

 he had another attack of amnesia, lasting three 

 months, and during this time he remembered only 

 what had happened in his previous attack. 



States of double or triple consciousness are 

 either disorders of memory, or instances of suspen- 

 sion of the higher volitional powers, being then 

 cases of hypnotism or of the epileptic automatic 



