SCIENCE. 



[Vol. XX. No 511 



earth- currents have anything to do with such dispositions of mat- 

 ter as the renewed deposit of ores asserted of certain dry mines 

 and tunnels; but no rock-bed, probably, is dry enough to demand 

 such an explanation, wliich itself requires a great deal of explaining. 



In this connection I will add that a hexagonal crystallization 

 in Mars, occurring to the mind of one of your correspondents, is 

 as wild as the canal idea. The radiating lines are on too vast a 

 ■scale ; and there is nothing in any known crystallizations to favor 

 the idea, unless it be the little six-rayed stars of frost spicules, 

 from which the jump to Marfan continents is too great. The 

 radiations have their counterpart in the old volcanic surface of 

 the moon and some analogous facts on the earth ; also in moun- 

 tain system " knots," Himalayan or other. 



On the whole, the action of lunar and solar tides on planets 

 while in a viscous condition, with more or less crust, is the only 

 hypothesis that so far promises well, in explanation of the re- 

 markable lines of the earth and Mars, notwithstanding the diffi - 

 culties mentioned. 



Yo ikera, N.Y., Oct. 27. 



RESDUAL PERSON.ALITY. 



EY ARTHtJR E. EOSTWICK. PH.D , MONTCLAIR, N. J. 



Evidence is not wanting to show that what we call personality 

 is an extremely complex thing, the sum of subsidiary personali- 

 ties which now shift and change like the figures in a kaleidoscope, 

 and again, becoming sharply defined under some abnormal con- 

 dition, crvstallize into two or more distinct groups of elements, 

 ■which alternately sleep and wake or even co-exist. These com- 

 plex elements may be so unstable, the groups composing them 

 constantly breaking up and forming new combinations, that the 

 idea of multiple personality does not naturally attach itself to 

 theiB ; it is only -when they become stable, and especially when 

 each exhibits a well-defined consciousness, that we begin to think 

 of such a thing. But, besides the abnormal and diseased con- 

 ditions which cause such a separation or crystallization, there are 

 other conditions in which it appears somewhat less distinctly. 

 To one class of these I desire to call attention very briefly — to 

 that embracing wliat may be called cases of residual personality. 



Residual phenomena of all kinds are particularly interesting 

 and instructive, especially those where the few things remaining 

 in a group after many have been removed differ widely in their 

 collective properties from those that have been taken away, while 

 these latter are not in any way distinguishable from tluse of the 

 sum of both before the division. This is the case often with resid- 

 ual personality. Nothing is more common than for a group of 

 elements in what we call a person to be differentiated in one of 

 various ways, leaving behind a residual group differing altogether 

 in its characteristics, though the differentiated group represents 

 to us, and is indeed considered to be identical with, the original 

 person. 



The commonest method of such differentiation is sleep. The 

 elements which sleep, are, as it were, subtracted from the normal 

 personaiity, but there is usually left behind a very curious some- 

 thing — illogical, credulous, fantastic — whose nightlj' experiences 

 the whole re-united person recollects in the morning as dreams. 

 The next commonest case is that of the absent minded person. 

 The major part of the person being absorbed in mental processes 

 of some sort, the residual person lives its own separate mental life, 

 thinks, feels, and wills by itself, and perhaps carries on a train of 

 processes which is continuous with a preceding train carried on 

 under similar circumstances the day before. This residual person 

 may act very mechanically ; the re-united person may fail to recol- 

 lect what its acts or thoughts were and be surprised to find how 

 it has been making use of his limbs while he — what he vainly 

 regards as the one unalterable ego — has been absorbed in thought; 

 but, on the other hand, it may be perfectly conscious, and may 

 earrj on an entirely different train of thought of its own. Almost 

 always, however, it is eccentric, and betrays a weakness at one 

 point or another. 



For instance, a suburban resident, whom we will call A, is 

 accustomed on landing at the New York side of the ferry to aban- 

 don the mechanical task of walking to his office entirely to his 



residual personality, and to give up the major part of himself to 

 thought. The two personalities act often with perfect — always 

 with practical — separateness, the residual person being quite 

 equal to the low task of evading vehicles, steering clear of 

 passers-by, and turning the proper corners. When the office is 

 reached and the two persons again become one, it is often a diffi- 

 cult task to remember any circumstances of the walk. On one 

 occasion, however, A left the Aslor Library on Lafayette Place, 

 as he supposed, intending to walk down Clinton Place. To do 

 this he must turn first to the left, then to the right, and then 

 again to the left. He turned once to the left, and after some 

 time became dimly conscious that he had walked for a longtime, 

 and that the place for the second turn had not been reached. 

 Coming to himself, he found himself far down Broadway. Trac- 

 ing back his course mentally, he discovered that he had been in 

 the Mercantile Library instead of the Astor; his first turn there- 

 fore had taken him down Broadway, and he of course did not 

 reach the place for the second. Mark now the peculiarities of 

 his residual person. It knew just where it was to turn and in 

 what direction, and had sense enough to be uneasy when it did 

 not come to the proper place to turn, but it had not intelligence 

 enough to know that it was on the wrong street. Its mind was 

 too weak to be trusted further than it was accustomed to go. 

 This residual person, in short, was about on a par with a harm- 

 less idiot. 



Again, B, a New Yorker, is walking along absorbed in aprocess 

 of thought, when his residual personality sees his friend C ap- 

 proaching. It is not astonished, for he is near C's lodgings, but 

 as the person supposed to be C comes nearer, it sees that he only 

 slightly resembles C; he has on shabby clothes, and his face is 

 entirely different. The natural conclusion would be that the per- 

 son approaching was not C. The residual person, however, does 

 not argue thus It concludes at once that C has greatly changed ; 

 that he has become poor, an<l that his appearance has altered for 

 the worse. Pity and surprise are plainly felt by the residual 

 person. During these mental processes, so similar to those of a 

 dream-residual, the major person has kept on with his own t;rain 

 of thought. Finally, however, on the close approach of the sup- 

 posed C, they unite in a flash into the normal person, the two 

 separate consciousnesses become one, and tlie truth is recognized 

 at once. No doubt these cases can be paralleled by thousands of 

 others. It seems to me that they are as true instances of double 

 personality as any exhibited by epileptic or hypnotic persons. 



Why should the residual person differso from the normal, while 

 the differentiated person is precisely like the normal ? If we take 

 199 gallons of water from 200, is not the remaining gallon still 

 water? There are many mathematical analogies. In geometry, 

 if vve draw a parallel to the bas^ of a triangle we thereby cut off 

 a precisely similar triangle, yet what is left has no resemblance to 

 a triangle. This analogy, carried out, would point to a consider- 

 ation of personality as a function of position or arrangement of 

 elements, as chemical isomers are functions of the position of their 

 constituent atoms. But an algebraic analogy, which ties us down 

 to no such hypothesis, probably comes nearer the truth. Consider 

 the identical equation {X + Y) — {^a X + b Y) =(1 — a) X + 

 (1 — b)Y. If a = b. the ratio of the two terms of minuend, sub- 



trahend, and remainder, each = — . But if a and b differ very 

 little from unity and from each other, then ,-may be sensibly 



1-b 



the terms of the subtrahend will be sensibly that of the terms of 

 the minuend, while that of the terms of the remainder may differ 

 greatly from both. In the same way, by extending the number of 

 terms, we may subtract from any polynomial what is sensibly a 

 sub-multiple of it, and yet leave a remainder whose terms bear a 

 very great disproportion. Hence it is, no doubt, that the removal 

 of a group of elements of personality that seems to represent one's 

 normal self may leave a residue so different and so incongruous. 

 It will be observed that what has been said is entirely indepen- 

 dent of any hypothesis as to the nature of the elements of per- 

 sonality and the mode of their combination. 



