LEFT-HANDEDNESS.*
THE very term "the right hand" is in itself but an arbitrary expression, for it has not been proved that the right hand, per se, is the better of the two, though it has since the begin- ning of history been the chosen agent of man's physical will. According to Sir Daniel Wilson, the majority of us have no decided preference for either hand, but education and imitation and inheritance tend to the use of the right hand for special efforts. The observations made by a colleague of Sir Daniel's • The Bight Saud Left-Handedness. By Sir Daniel Wilson. Nature Series. London: Macmillan and Co. on his own daughter seem to show that a distinct preference for the right hand in making special efforts was noticed about the age of seven months, and later on it is recorded that a father did not notice in his children any bias towards the use of either hand. These observations perhaps embody the real essence of the problem. While there is no need to perform any difficult work, to put forth any particular strength or particular skill, one hand is as good as the other ; when an action has to be performed requiring unusual strength or skill, the one hand must be chosen, and the choice thereof must be from hereditary instinct or knowledge of its superiority by training. It is obvious that, however advantageous ambidex- terity may be, the preference must be given to one hand, so that we may lose no time ; else would presence of mind be but a useless quality. We can quite imagine that an individual whose ambidexterity was absolute might lose time, possibly his life, from the possession of a dubious will ; he would be in the position of the proverbial donkey between two haystacks.
The question now is : Why has the hand we call " right " been chosen to express skilled action in its various forms? The most celebrated anatomists and physiologists have been tempted to propound theories, all equally profound and in- conclusive. Some thought that because the heart was on the left side, the right was naturally selected to give that vital organ the more room to work in. There is a simple, direct— nay, seemingly natural force about this reasoning which is not to be despised. It is founded on fact, and, it is fairly safe to say, must have exercised at least a prejudicial effect on the spontaneous use of the left hand. Then, again, the disposition of the viscera, the preponderance of the right side is supposed to lend more effect to the muscles of the right side, which are also said to be better nourished, through the position of one of the arteries. That the position of the centre of gravity might affect the capacity of the muscles, is reasonable to suppose, as it also would be to infer that the greater capacity of the right lung shifts the centre of gravity. Two physiologists are quoted as suggesting this cause,—one, indeed, has elaborated his theory so as to account for left-handedness. We are told, accordingly, that in the majority of cases the centre of gravity on the right side is above the transverse axis; hence the left foot is used for balancing, and the right limb has the muscular part allotted to it ; consequently, man is right-footed. When the two coincide, the individual is ambidextrous ; and when the centre of gravity is below the transverse axis, the individual is left-handed, a classification which is summed up in the proposition that broad shoulders, muscular arms, large head, and a long neck tend to elevate the centre, and broad hip and strong legs to bring it down. But against this elaborate theory, the numerous examples of left-handedness must he set ; the preference for the left hand in these cases is so evidently natural, so irresistible and instinctive, that the theory which fails to account for its possession by individuals cannot be seriously held. Sir Daniel Wilson is left-handed, and sees nothing extraordinary in the supposed superiority of left-handed men. It might be thought by some that the unfamiliar sight of the left band performing nice operations is in itself calculated to magnify and enhance the actual skill of the left-handed individual ; and that as only the few, those who possess the most powerfully instinctive use of the left hand, preserve, in spite of long-descended conventionality, their natural bias, we must obviously see the best examples. Now, the first of these contentions is apparently true, and the second absolutely so, and illustrates once more the survival of the fittest. Left-handers are notably of more than the average strength, and a great deal more than the average accuracy of eye. Leonardo da Vinci and Hans Holbein, the writer reminds us, were left-handed. Left-handed batsmen are noted for hitting, left-handed fielders for smartness, and left- handed bowlers are generally fast. We know a gentleman, not a straight bat, whose back-play is a perpetual source of astonishment to the spectators. But now comes in a factor of unknown quantity. One would think that where conven- tional usage has obtained from the left-handed one particular set of motions for the right hand, it would be one requiring but average skill. But is this so ? The three arts of cricket are distributed amongst left-handed people in the most arbitrary and apparently inconsistent manner ; most of them bat left-handed, but many bowl with the right, and some bat with the right and bowl with the left.
No doubt it would be found that, on the whole, those actions requiring the utmost nicety and the greatest accord between eye and limb are allotted to the superior hand ; spontaneous gestures and unstudied actions would also be performed by the same hand. It is remarkable that with the majority of people the neglected left hand is not in mere strength inferior to the right. We have heard truly right-handed people actually declare that their left hand is the stronger, and from the present writer's own experience he knows this to be the case. This may be from the mechanical advantage and better balance of the body, the right side being heavier, or it may be due to the large muscles of the unused arm being less hampered by the development of other muscles. It is difficult in these cases to say which is the "right" hand, for the fact that the unused arm is the stronger does not imply ambidexterity, nor can we justly give the precedence to strength over dexterity. Moreover, we cannot call the hand that excels in one series of dexterous motions the superior hand, if it can be shown that the other is chosen to perform an act which, apparently trifling, may require some knack or nicety of touch. It is the hand put forth in emergency, when taken by surprise, that makes a spontaneous gesture, the hand that acts first, which is the " right " hand.
Though with most of us the tendency to prefer one hand, apart from the customary usage, is undoubtedly not very pronounced, yet it is extraordinarily strong in many. Unfor- tunately, it can only be observed in the left hand, but it is of so obstinate and persisting a nature as to place beyond doubt the origin of the predisposing cause in the brain. It is a true instinct, and as such must be due to some organic peculiarity. We read in Left-Handedness of a boy whose left hand was bound behind him by his narrow-minded mother, till they feared it was permanently injured ; yet he began to use it at once, on its release : and we have heard of a young girl whose left hand was tied in a bag to compel her to sew with the right, all to no purpose. But the greater number of left-handed people become merged in the ambidextrous,—that is to say, the class whose wrong hand is educated to an equality with their " right," in all except those movements requiring instinctive rapidity of motion or instinctive nicety of judgment. The term " ambidexterity " is a sufficiently near enough one to define the peculiar quality, though we doubt if truly ambidextrous persons who absolutely embody the signifi- cance of the word, are not almost as rare as black swans. Not only would such an individual be unnatural, and suffer from embarrassment, but would be, humanly speaking, not quite possible,—one of man's hands, he being a manufacturer, must have the supremacy. A classic instance of ambidexterity was Asteropwus, who wounded Achilles, and a modern instance is an artist known to the writer who sometimes paints with both hands at once.
Anatomists are coming to the conclusion, and Sir Daniel agrees with them, that we must look for the origin of this preference in the greater development of that part of the brain which directs the limb. The left part of the brain is said to be heavier, but the investigation is a delicate one, the results by no means definite; it has yet to be proved that man is born with his brain so partially developed. The balance, as the writer says elsewhere, is, if we eliminate the hereditary tendency from custom and the overwhelming pressure of to-day, with its multitude of arts and pastimes, pro- bably very even. There is a reason, too, for this balance, which seems to us as beautiful as it is simple. It is this. If man is to preserve his bilateral symmetry through successive generations, this object would be beyond his reach, did he continue to be born with this predisposing cause. In spite of the fact that he must use one hand in preference to the other, and his long-descended custom, and other circum- stances, he still preserves his symmetry, and remains the most perfectly symmetrical of all creatures. That he does so, that the continued use of one hand has not increased the predis- position to use that hand abnormally, can only be one more provision of the Creator. Let us suppose, then, that the unsymmetrical position, though perfectly arranged disposition. of the vital organs has suggested to man the use of the right hand, but that he has not been allowed to exaggerate this pre- ference into a deformity. All theories are unsatisfactory, however, even that which would solve the difficulty by assuming that the left necessarily became the left because it had to hold the heart-defending shield, for post-pliocene man generally used his right hand.
It does not seem to us that Sir Daniel Wilson has advanced any nearer the solution of the problem he has set himself, the cause of the preferential use of the right hand. Sir Daniel Wilson writes clearly and pleasantly ; but he might have found more matter if he knew more about games, and we notice that in stating the fact of the boxer's trained ambidexterity, he forgets to mention the fact that the boxer is taught to hit with the left and guard with the right.
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