sentiments of a religious nature, of terror and of aversion, and in
giving a fallacious sense of their being natural instincts. But it
will be observed that the circumstances from which these influences
proceed, affect large classes simultaneously, forming a kind of
atmosphere in which every member of them passes his life. They
produce the cast of mind that distinguishes an Englishman from a
foreigner, and one class of Englishman from another, but they have
little influence in creating the differences that exist between
individuals of the same class.
HISTORY OF TWINS.
The exceedingly close resemblance attributed to twins has been the
subject of many novels and plays, and most persons have felt a
desire to know upon what basis of truth those works of fiction may
rest. But twins have a special claim upon our attention; it is, that
their history affords means of distinguishing between the effects of
tendencies received at birth, and of those that were imposed by the
special circumstances of their after lives. The objection to
statistical evidence in proof of the inheritance of peculiar
faculties has always been: "The persons whom you compare may have
lived under similar social conditions and have had similar
advantages of education, but such prominent conditions are only a
small part of those that determine the future of each man's life. It
is to trifling accidental circumstances that the bent of his
disposition and his success are mainly due, and these you leave
wholly out of account--in fact, they do not admit of being tabulated,
and therefore your statistics, however plausible at first sight, are
really of very little use." No method of inquiry which I had
previously been able to carry out--and I have tried many methods--is
wholly free from this objection. I have therefore attacked the
problem from the opposite side, seeking for some new method by which
it would be possible to weigh in just scales the effects of Nature
and Nurture, and to ascertain their respective shares in framing the
disposition and intellectual ability of men. The life-history of
twins supplies what I wanted. We may begin by inquiring about twins
who were closely alike in boyhood and youth, and who were educated
together for many years, and learn whether they subsequently grew
unlike, and, if so, what the main causes were which, in the opinion
of the family, produced the dissimilarity. In this way we can obtain
direct evidence of the kind we want. Again, we may obtain yet more
valuable evidence by a converse method. We can inquire into the
history of twins who were exceedingly unlike in childhood, and learn
how far their characters became assimilated under the influence of
identical nurture, inasmuch as they had the same home, the same
teachers, the same associates, and in every other respect the same
surroundings.
My materials were obtained by sending circulars of inquiry to
persons who were either twins themselves or near relations of twins.
The printed questions were in thirteen groups; the last of them
asked for the addresses of other twins known to the recipient, who
might be likely to respond if I wrote to them. This happily led to a
continually widening circle of correspondence, which I pursued until
enough material was accumulated for a general reconnaisance of the
subject.
There is a large literature relating to twins in their purely
surgical and physiological aspect. The reader interested in this
should consult _Die Lehre von den Zwillingen_, von L. Kleinwächter,
Prag. 1871. It is full of references, but it is also unhappily
disfigured by a number of numerical misprints, especially in page 26.
I have not found any book that treats of twins from my present point
of view.
The reader will easily understand that the word "twins" is a vague
expression, which covers two very dissimilar events--the one
corresponding to the progeny of animals that usually bear more than
one at a birth, each of the progeny being derived from a separate
ovum, while the other event is due to the development of two
germinal spots in the same ovum. In the latter case they are
enveloped in the same membrane, and all such twins are found
invariably to be of the same sex. The consequence of this is, that I
find a curious discontinuity in my results. One would have expected
that twins would commonly be found to possess a certain average
likeness to one another; that a few would greatly exceed that
average likeness, and a few would greatly fall short of it. But this
is not at all the case. Extreme similarity and extreme dissimilarity
between twins of the same sex are nearly as common as moderate
resemblance. When the twins are a boy and a girl, they are never
closely alike; in fact, their origin is never due to the development
of two germinal spots in the same ovum.
I received about eighty returns of cases of close similarity,
thirty-five of which entered into many instructive details. In a few
of these not a single point of difference could be specified. In the
remainder, the colour of the hair and eyes were almost always
identical; the height, weight, and strength were nearly so.
Nevertheless, I have a few cases of a notable difference in height,
weight, and strength, although the resemblance was otherwise very
near. The manner and personal address of the thirty-five pairs of
twins are usually described as very similar, but accompanied by a
slight difference of expression, familiar to near relatives, though
unperceived by strangers. The intonation of the voice when speaking
is commonly the same, but it frequently happens that the twins sing
in different keys. Most singularly, the one point in which
similarity is rare is the handwriting. I cannot account for this,
considering how strongly handwriting runs in families, but I am sure
of the fact. I have only one case in which nobody, not even the twins
themselves, could distinguish their own notes of lectures, etc.;
barely two or three in which the handwriting was undistinguishable
by others, and only a few in which it was described as closely alike.
On the other hand, I have many in which it is stated to be unlike,
and some in which it is alluded to as the only point of difference.
It would appear that the handwriting is a very delicate test of
difference in organisation--a conclusion which I commend to the
notice of enthusiasts in the art of discovering character by the
handwriting.
One of my inquiries was for anecdotes regarding mistakes made
between the twins by their near relatives. The replies are numerous,
but not very varied in character. When the twins are children, they
are usually distinguished by ribbons tied round the wrist or neck;
nevertheless the one is sometimes fed, physicked, and whipped by
mistake for the other, and the description of these little domestic
catastrophes was usually given by the mother, in a phraseology that
is somewhat touching by reason of its seriousness. I have one case
in which a doubt remains whether the children were not changed in
their bath, and the presumed A is not really B, and _vice versâ_. In
another case, an artist was engaged on the portraits of twins who
were between three and four years of age; he had to lay aside his
work for three weeks, and, on resuming it, could not tell to which
child the respective likenesses he had in hand belonged. The
mistakes become less numerous on the part of the mother during the
boyhood and girlhood of the twins, but are almost as frequent as
before on the part of strangers. I have many instances of tutors
being unable to distinguish their twin pupils. Two girls used
regularly to impose on their music teacher when one of them wanted a
whole holiday; they had their lessons at separate hours, and the one
girl sacrificed herself to receive two lessons on the same day,
while the other one enjoyed herself from morning to evening. Here is
a brief and comprehensive account:--
"Exactly alike in all, their schoolmasters never could tell them
apart; at dancing parties they constantly changed partners without
discovery; their close resemblance is scarcely diminished by age."
The following is a typical schoolboy anecdote:--
"Two twins were fond of playing tricks, and complaints were
frequently made; but the boys would never own which was the guilty
one, and the complainants were never certain which of the two he was.
One head master used to say he would never flog the innocent for the
guilty, and another used to flog both."
No less than nine anecdotes have reached me of a twin seeing his or
her reflection in a looking-glass, and addressing it in the belief
it was the other twin in person.
I have many anecdotes of mistakes when the twins were nearly grown up.
Thus:--
"Amusing scenes occurred at college when one twin came to visit the
other; the porter on one occasion refusing to let the visitor out of
the college gates, for, though they stood side by side, he professed
ignorance as to which he ought to allow to depart."
Children are usually quick in distinguishing between their parent
and his or her twin; but I have two cases to the contrary. Thus, the
daughter of a twin says:--
"Such was the marvellous similarity of their features, voice, manner,
etc., that I remember, as a child, being very much puzzled, and I
think, had my aunt lived much with us, I should have ended by
thinking I had two mothers."
In the other case, a father who was a twin, remarks of himself and
his brother:--
"We were extremely alike, and are so at this moment, so much so that
our children up to five and six years old did not know us apart."
I have four or five instances of doubt during an engagement of
marriage. Thus:--
"A married first, but both twins met the lady together for the first
time, and fell in love with her there and then. A managed to see her
home and to gain her affection, though B went sometimes courting in
his place, and neither the lady nor her parents could tell which was
which."
I have also a German letter, written in quaint terms, about twin
brothers who married sisters, but could not easily be distinguished
by them.[13] In the well-known novel by Mr. Wilkie Collins of
_Poor Miss Finch_, the blind girl distinguishes the twin she loves
by the touch of his hand, which gives her a thrill that the touch of
the other brother does not. Philosophers have not, I believe, as yet
investigated the conditions of such thrills; but I have a case in
which Miss Finch's test would have failed. Two persons, both friends
of a certain twin lady, told me that she had frequently remarked to
them that "kissing her twin sister was not like kissing her other
sisters, but like kissing herself--her own hand, for example."
It would be an interesting experiment for twins who were closely
alike to try how far dogs could distinguish them by scent.
[Footnote 13: I take this opportunity of withdrawing an anecdote,
happily of no great importance, published in _Men of Science_, p. 14,
about a man personating his twin brother for a joke at supper, and
not being discovered by his wife. It was told me on good authority;
but I have reason to doubt the fact, as the story is not known to
the son of one of the twins. However, the twins in question were
extraordinarily alike, and I have many anecdotes about them sent me
by the latter gentleman.]
I have a few anecdotes of strange mistakes made between twins in
adult life. Thus, an officer writes:--
"On one occasion when I returned from foreign service my father
turned to me and said, 'I thought you were in London,' thinking I
was my brother--yet he had not seen me for nearly four years--our
resemblance was so great."
The next and last anecdote I shall give is, perhaps, the most
remarkable of those I have; it was sent me by the brother of the
twins, who were in middle life at the time of its occurrence:--
"A was again coming home from India, on leave; the ship did not
arrive for some days after it was due; the twin brother B had come
up from his quarters to receive A, and their old mother was very
nervous. One morning A rushed in saying, 'Oh, mother, how are you?'
Her answer was, 'No, B, it's a bad joke; you know how anxious I am!'
and it was a little time before A could persuade her that he was the
real man."
Enough has been said to prove that an extremely close personal
resemblance frequently exists between twins of the same sex; and that,
although the resemblance usually diminishes as they grow into
manhood and womanhood, some cases occur in which the diminution of
resemblance is hardly perceptible. It must be borne in mind that it
is not necessary to ascribe the divergence of development, when it
occurs, to the effect of different nurtures, but it is quite
possible that it may be due to the late appearance of qualities
inherited at birth, though dormant in early life, like gout. To this
I shall recur.
There is a curious feature in the character of the resemblance
between twins, which has been alluded to by a few correspondents; it
is well illustrated by the following quotations. A mother of twins
says:--
"There seemed to be a sort of interchangeable likeness in expression,
that often gave to each the effect of being more like his brother
than himself."
Again, two twin brothers, writing to me, after analysing their
points of resemblance, which are close and numerous, and pointing
out certain shades of difference, add--
"These seem to have marked us through life, though for a while, when
we were first separated, the one to go to business, and the other to
college, our respective characters were inverted; we both think that
at that time we each ran into the character of the other. The proof
of this consists in our own recollections, in our correspondence by
letter, and in the views which we then took of matters in which we
were interested."
In explanation of this apparent interchangeableness, we must
recollect that no character is simple, and that in twins who
strongly resemble each other, every expression in the one may be
matched by a corresponding expression in the other, but it does not
follow that the same expression should be the prevalent one in both
cases. Now it is by their prevalent expressions that we should
distinguish between the twins; consequently when one twin has
temporarily the expression which is the prevalent one in his brother,
he is apt to be mistaken for him. There are also cases where the
development of the two twins is not strictly _pari passu_; they
reach the same goal at the same time, but not by identical stages.
Thus: A is born the larger, then B overtakes and surpasses A, and is
in his turn overtaken by A, the end being that the twins, on
reaching adult life, are of the same size. This process would aid in
giving an interchangeable likeness at certain periods of their growth,
and is undoubtedly due to nature more frequently than to nurture.
Among my thirty-five detailed cases of close similarity, there are
no less than seven in which both twins suffered from some special
ailment or had some exceptional peculiarity. One twin writes that
she and her sister "have both the defect of not being able to come
downstairs quickly, which, however, was not born with them, but came
on at the age of twenty." Three pairs of twins have peculiarities in
their fingers; in one case it consists in a slight congenital
flexure of one of the joints of the little finger; it was inherited
from a grandmother, but neither parents, nor brothers, nor sisters
show the least trace of it. In another case the twins have a
peculiar way of bending the fingers, and there was a faint tendency
to the same peculiarity in the mother, but in her alone of all the
family. In a third case, about which I made a few inquiries, which
is given by Mr. Darwin, but is not included in my returns, there was
no known family tendency to the peculiarity which was observed in
the twins of having a crooked little finger. In another pair of twins,
one was born ruptured, and the other became so at six months old.
Two twins at the age of twenty-three were attacked by toothache, and
the same tooth had to be extracted in each case. There are curious
and close correspondences mentioned in the falling off of the hair.
Two cases are mentioned of death from the same disease; one of which
is very affecting. The outline of the story was that the twins were
closely alike and singularly attached, and had identical tastes;
they both obtained Government clerkships, and kept house together,
when one sickened and died of Bright's disease, and the other also
sickened of the same disease and died seven months later.
Both twins were apt to sicken at the same time in no less than nine
out of the thirty-five cases. Either their illnesses, to which I
refer, were non-contagious, or, if contagious, the twins caught them
simultaneously; they did not catch them the one from the other. This
implies so intimate a constitutional resemblance, that it is proper
to give some quotations in evidence. Thus, the father of two twins
says:--
"Their general health is closely alike; whenever one of them has an
illness, the other invariably has the same within a day or two, and
they usually recover in the same order. Such has been the case with
whooping-cough, chicken-pox, and measles; also with slight bilious
attacks, which they have successively. Latterly, they had a feverish
attack at the same time."
Another parent of twins says:--
"If anything ails one of them, identical symptoms _nearly always_
appear in the other; this has been singularly visible in two
instances during the last two months. Thus, when in London, one fell
ill with a violent attack of dysentery, and within twenty-four hours
the other had precisely the same symptoms."
A medical man writes of twins with whom he is well acquainted:--
"Whilst I knew them, for a period of two years, there was not the
slightest tendency towards a difference in body or mind; external
influences seemed powerless to produce any dissimilarity."
The mother of two other twins, after describing how they were ill
simultaneously up to the age of fifteen, adds, that they shed their
first milk-teeth within a few hours of each other.
Trousseau has a very remarkable case (in the chapter on Asthma) in
his important work _Clinique M. édicale_. (In the edition of 1873 it
is in vol. ii. p. 473.) It was quoted at length in the original
French, in Mr. Darwin's _Variation under Domestication_, vol. ii. p.
252. The following is a translation:--
"I attended twin brothers so extraordinarily alike, that it was
impossible for me to tell which was which, without seeing them side
by side. But their physical likeness extended still deeper, for they
had, so to speak, a yet more remarkable pathological resemblance.
Thus, one of them, whom I saw at the Néothermes at Paris, suffering
from rheumatic ophthalmia, said to me, 'At this instant my brother
must be having an ophthalmia like mine;' and, as I had exclaimed
against such an assertion, he showed me a few days afterwards a
letter just received by him from his brother, who was at that time
at Vienna, and who expressed himself in these words--'I have my
ophthalmia; you must be having yours.' However singular this story
may appear, the fact is none the less exact; it has not been told to
me by others, but I have seen it myself; and I have seen other
analogous cases in my practice. These twins were also asthmatic, and
asthmatic to a frightful degree. Though born in Marseilles, they
were never able to stay in that town, where their business affairs
required them to go, without having an attack. Still more strange,
it was sufficient for them to get away only as far as Toulon in
order to be cured of the attack caught at Marseilles. They travelled
continually, and in all countries, on business affairs, and they
remarked that certain localities were extremely hurtful to them, and
that in others they were free from all asthmatic symptoms."
I do not like to pass over here a most dramatic tale in the
_Psychologie Morbide_ of Dr. J. Moreau (de Tours), M. édecin de
l'Hospice de Bicêtre. Paris, 1859, p. 172. He speaks "of two twin
brothers who had been confined, on account of monomania, at Bicêtre":--
"Physically the two young men are so nearly alike that the one is
easily mistaken for the other. Morally, their resemblance is no less
complete, and is most remarkable in its details. Thus, their
dominant ideas are absolutely the same. They both consider
themselves subject to imaginary persecutions; the same enemies have
sworn their destruction, and employ the same means to effect it.
Both have hallucinations of hearing. They are both of them
melancholy and morose; they never address a word to anybody, and
will hardly answer the questions that others address to them. They
always keep apart, and never communicate with one another. An
extremely curious fact which has been frequently noted by the
superintendents of their section of the hospital, and by myself, is
this: From time to time, at very irregular intervals of two, three,
and many months, without appreciable cause, and by the purely
spontaneous effect of their illness, a very marked change takes
place in the condition of the two brothers. Both of them, at the
same time, and often on the same day, rouse themselves from their
habitual stupor and prostration; they make the same complaints, and
they come of their own accord to the physician, with an urgent
request to be liberated. I have seen this strange thing occur, even
when they were some miles apart, the one being at Bicêtre, and the
other living at Saint-Anne."
I sent a copy of this passage to the principal authorities among the
physicians to the insane in England, asking if they had ever
witnessed any similar case. In reply, I have received three
noteworthy instances, but none to be compared in their exact
parallelism with that just given. The details of these three cases
are painful, and it is not necessary to my general purpose that I
should further allude to them.
There is another curious French case of insanity in twins, which was
pointed out to me by Sir James Paget, described by Dr. Baume in the
_Annales M. édico-Psychologiques_, 4 série, vol. i., 1863, p. 312,
of which the following is an abstract. The original contains a few
more details, but is too long to quote: Francois and Martin, fifty
years of age, worked as railroad contractors between Quimper and
Châteaulin. Martin had twice slight attacks of insanity. On January 15
a box was robbed in which the twins had deposited their savings. On
the night of January 23-24 both François (who lodged at Quimper) and
Martin (who lived with his wife and children at St. Lorette, two
leagues from Quimper) had the same dream at the same hour, three a.m.,
and both awoke with a violent start, calling out, "I have caught the
thief! I have caught the thief! they are doing mischief to my brother!"
They were both of them extremely agitated, and gave way to similar
extravagances, dancing and leaping.
Martin sprang on his grandchild, declaring that he was the thief,
and would have strangled him if he had not been prevented; he then
became steadily worse, complained of violent pains in his head, went
out of doors on some excuse, and tried to drown himself in the river
Steir, but was forcibly stopped by his son, who had watched and
followed him. He was then taken to an asylum by gendarmes, where he
died in three hours. Francois, on his part, calmed down on the
morning of the 24th, and employed the day in inquiring about the
robbery. By a strange chance, he crossed his brother's path at the
moment when the latter was struggling with the gendarmes; then he
himself became maddened, giving way to extravagant gestures and using
incoherent language (similar to that of his brother). He then asked
to be bled, which was done, and afterwards, declaring himself to be
better, went out on the pretext of executing some commission, but
really to drown himself in the River Steir, which he actually did,
at the very spot where Martin had attempted to do the same thing a
few hours previously.