220 



NATURE 



[July 7, 1892 



The subject is one that is beset with peculiar difficulties, 

 and one in which extreme caution is necessary in drawing 

 anything like definite conclusions. But it is one that is 

 throwing, and is likely to throw, important side light on 

 normal psychology, and one that may prove helpful in 

 elucidating the difficult problem of the nature of the 

 association of brain and consciousness. It will only be 

 possible in the space at our disposal to indicate the nature 

 of some of the evidence M. Binet adduces, and the in- 

 terpretation suggested by this learned and lucid writer. 



The phenomenaof so-called spontaneous somnambulism 

 are somewhat as follows. The patient is, we will say, a 

 dull and melancholy young woman. She falls into a deep 

 and prolonged sleep, or suffers from an hysterical or con- 

 vulsive crisis. On waking from the sleep, or emerging 

 from the crisis, she is in an altered condition, with little or 

 no memory of her previous life, and no apparent know- 

 ledge of her friends and relations. Her character is 

 changed : no longer dull and melancholy, she is bright 

 and merry. In this state she remains for a time, learning 

 anew the ways of the world, and daily profiting by her fresh 

 experiences. Then she falls again into deep slumber, or 

 other crisis, from which she emerges her old self once 

 more, taking up her normal dull and melancholy life just 

 where she left it. She remembers nothing that happened 

 in her abnormal or second state. There is no continuity 

 between the two. Such alterations of personality may 

 continue at varying intervals for many years. 



Somewhat similar are the phenomena observed in the 

 somnambulism induced through hypnotic suggestion. M. 

 Janet's subject, Ldonie, is a serious and rather sad person, 

 calm and slow, very mild with everyone, and extremely 

 timid. Hypnotized, she becomes a different being. She 

 keeps her eyes closed, but her other senses are abnormally 

 acute. She is gay, noisy, and restless ; good-natured, 

 but with a tendency to irony and sharp jesting. In this 

 condition she repudiates her former self. " That good 

 woman is not myself," she says, " she is too stupid ! " 



M. Binet, summarizing the principal modifications of 

 memory in hypnotic somnambulism, says that the subject, 

 during the normal condition, remembers nothing of the 

 events which have taken place during somnambulism, but 

 that, when hypnotized, he may remember not only the 

 occurrences in former somnambulisms, but also those 

 which belong to the normal state. There is thus some 

 continuity of the normal into the hypnotic personality, but 

 none from the hypnotic to the normal. " Le livre de la 

 vie somnambulique se ferme au rdveil, et la personne 

 normale ne pent pas le lire." 



But though there is no conscious memory in the waking 

 state of what has occurred during somnambulism, it is 

 said to be possible to unseal the register thereof through 

 automatic writing. A fact is told to the subject in the 

 state of somnambulism under hypnosis, and the subject 

 is then restored to the normal state. He has no recollection 

 of the fact, and knows nothing about it. But slip a pencil 

 between his fingers, hiding the hand from his eyes by 

 means of a screen, and he will write down the fact auto- 

 matically (Gurney). 



In cases of so-called "negative hallucination" .or 

 " systematic anaesthesia," the subject under hypnotic sug- 

 gestion neglects and is apparently blind to certain objects. 

 For example, two out of a number of blank cards are 

 NO. I 184, VOL. 46] 



marked with a cross, and the subject is made blind to 

 these. If she be given a dozen cards, and among them 

 these two, and if she be asked to count the cards, she will 

 neglect these two and reply that there are ten. But if a 

 pencil be slipped between her fingers, and she be asked 

 in a low voice how many cards there are, she will reply, 

 in automatic writing, two. And if she be asked, in the 

 same tone, why she said ten and neglected these two, she 

 will write in reply that " she could not see them." 



On the basis of such observations as are here briefly 

 summarized, and others for a description of which we must 

 refer our readers to the book itself, M. Binet contends 

 that, associated with the same physical individual, there 

 may be two (or more) personalities, both of which are 

 conscious. They may be co-existent or successive. 

 Anaesthesia is the barrier which separates co-existent 

 personalities : amnesia the barrier which separates suc- 

 cessive personalities. " En un mot, il peut y avoir chez 

 un meme individu, plurality de memoires, plurality de 

 consciences, plurality de personnalitds ; etchacunede ces 

 memoires, de ces consciences, de ces personnalites ne 

 connait que ce qui se passe sur son territoire." We do 

 not propose to discuss this position. Suffice it to say, 

 that for ourselves we see no satisfactory evidence of the 

 co-existence of two personalities both of which are 

 simultaneously conscious. Strange alterations and modi- 

 fications of personality may occur under peculiar 

 circumstances ; but this is something very different 

 from the supposed co-existence of two or more distinct 

 consciousnesses. C. Ll. M. 



OUR BOOK SHELF. 



Volcanoes : Past and Present. By Edward Hull, M.A., 

 LL.D., F.R.S. With Forty-one Illustrations and Four 

 Plates of Rock-sections. (London : Walter Scott, 

 1892.) 

 In this new volume of the " Contemporary Science 

 Series," Prof. Hull has given a very readable account of 

 the phenomena of volcanoes and earthquakes. A short 

 introduction to the subject of vulcanology is followed by 

 a sketch of the active and extinct volcanoes of Europe, 

 and this by an account of some of the " dormant or mori- 

 bund volcanoes of other parts of the world." From this 

 description of recent volcanoes, the author proceeds to 

 the consideration of the Tertiary volcanic districts of the 

 British Islands, and the pre-Tertiary volcanic rocks of 

 our own and other countries. The two concluding chap- 

 ters of the book are devoted to a consideration of the 

 remarkable eruption of Krakatab in 1 883, and the great 

 earthquakes which during the last few years have 

 attracted so much attention, with a discussion of some 

 of the volcanic and seismic problems suggested to the 

 author by his review of the phenomena. These problems 

 are classed by the author under the following heads : — 

 " The Ultimate Cause of Volcanic Action," " Lunar Vol- 

 canoes," and the question : " Are we living in an Epoch 

 of special Volcanic Activity ? " An appendix gives " A 

 Brief Account of the Principal Varieties of Volcanic 

 Rocks." 



In a little book of 270 pages it has of course been im- 

 possible for the author to do full justice to such a wide 

 circle of topics, and it is sometimes difficult to detect the 

 principle on which certain subjects have been included, 

 and others rejected by him. But the author may be 

 fairly credited with having accomplished his main object, 

 which he has defined as follows : " To illustrate the most 



