The truly left-handed, equally with the larger percentage of those who may be designated truly right-handed, are exceptionally dexterous; and to the former the idea that the instinctive impulse which influences their preference is a mere acquired habit, traceable mainly to some such bias as the mode of carrying in the nurse’s arms in infancy, is utterly untenable. The value of personal experience in determining some of the special points involved in this inquiry is obvious, and will excuse a reference to my own observations, as confirmed by a comparison with those of others equally affected, such as Professor Edward S. Morse, Dr. E. A. Reeve, a former pupil of my own, and my friend, Dr. John Rae, the Arctic explorer. The last remarked in a letter to me, confirming the idea of hereditary transmission: “Your case as to left-handedness seems very like my own. My mother was left-handed, and very neat-handed also. My father had a crooked little finger on the left hand. So have I.” Referring to personal experience, I may note as common to myself with other thoroughly left-handed persons, that, with an instinctive preference for the left hand, which equally resisted remonstrance, proffered rewards, and coercion, I nevertheless learned to use the pen in the right hand, apparently with no greater effort than other boys who pass through the preliminary stages of the art of penmanship. In this way the right hand was thoroughly educated, but the preferential instinct remained. The slate-pencil, the chalk, and penknife were still invariably used in the left hand, in spite of much opposition on the part of teachers; and in later years, when a taste for drawing has been cultivated with some degree of success, the pencil and brush are nearly always used in the left hand. At a comparatively early age the awkwardness of using the spoon and knife at table in the left hand was perceived and overcome. Yet even now, when much fatigued, or on occasion of unusual difficulty in carving a joint, the knife is instinctively transferred to the left hand. Alike in every case where unusual force is required, as in driving a large nail, wielding a heavy tool, or striking a blow with the fist, as well as in any operation demanding special delicacy, the left hand is employed. Thus, for example, though the pen is invariably used in the right hand in penmanship, the crow-quill and etching needle are no less uniformly employed in the left hand. Hence, accordingly, on proceeding to apply the test of the hand to the demotic writing of the Egyptians, by copying rapidly the Turin enchorial papyrus already referred to, first with the right hand and then with the left, while some of the characters were more accurately rendered as to slope, thickening of lines, and curve, with the one hand, and some with the other, I found it difficult to decide on the whole which hand executed the transcription with greater ease. In proof of the general facility thus acquired, I may add that I find no difficulty in drawing at the same time with a pencil in each hand, profiles of men or animals facing each other. The attempt to draw different objects, as a dog’s head with the one hand and a human profile with the other, is unsuccessful, owing to the complex mental operation involved; and in this case the co-operation is apt to be between the mind and the more facile hand. In the simultaneous drawing of reverse profiles there is what, to an ordinary observer, would appear to be thorough ambidexterity. Nevertheless, while there is in such cases of ambidexterity, characteristic of most left-handed persons, little less command of the right hand than in those exclusively right-handed, it is wholly acquired; nor, in my own experience, has the habit, fostered by the practice of upwards of seventy years, overcome the preferential use of the other hand.
When attending the meeting of the American Association for the Advancement of Science held at Buffalo in 1867, my attention was attracted by the facility with which Professor Edward S. Morse used his left hand when illustrating his communications by crayon drawings on the blackboard. His ability in thus appealing to the eye is well known. The Boston Evening Transcript, in commenting on a course of lectures delivered there, thus proceeds: “We must not omit to mention the wonderful skill displayed by Professor Morse in his blackboard drawings of illustrations, using either hand with facility, but working chiefly with the left hand. The rapidity, simplicity, and remarkable finish of these drawings elicited the heartiest applause of his audience.” Referring to the narrative of my own experience as a naturally left-handed person subjected to the usual right-hand training with pen, pencil, knife, etc., Professor Morse remarks in a letter to me: “I was particularly struck by the description of your experiences in the matter, for they so closely accord with my own: my teachers having in vain endeavoured to break off the use of the left hand, which only resulted in teaching me to use my right hand also. At a short distance, I can toss or throw with the right hand quite as accurately as I can with my left. But when it comes to flinging a stone or other object a long distance, I always use the left hand as coming the most natural. There are two things which I cannot possibly do with my right hand, and that is to drive a nail, or to carve, cut, or whittle. For several years I followed the occupation of mechanical draughtsman, and I may say that there was absolutely no preference in the use of either hand; and in marking labels, or lettering a plan, one hand was just as correct as the other.” I may add here that in my own case, though habitually using the pen in my right hand, yet when correcting a proof, or engaged in other disconnected writing, especially if using a pencil, I am apt to resort to the left hand without being conscious of the change. In drawing I rarely use the right hand; and for any specially delicate piece of work, should find it inadequate to the task.
The same facility is illustrated in the varying caligraphy of a letter of Professor Morse, in which he furnished me with the best practical illustration of the ambidextrous skill so frequently acquired by the left-handed. He thus writes: “You will observe that the first page is written with the right hand, the upper third of this page with the left hand, the usual way [but with reversed slope], the middle third of the page with the left hand, reversed [i.e. from right to left], and now I am again writing with the right hand. As I have habitually used the right hand in writing, I write more rapidly than with the other.” In the case of Professor Morse, I may add, the indications of hereditary transmission of left-handedness nearly correspond with my own. His maternal uncle, and also a cousin, are left-handed. In my case, the same habit appeared in a paternal uncle and a niece; and my grandson manifested at an early age a decided preference for the left hand. Even in the absence of such habitual use of both hands as Professor Morse practises, the command of the left hand in the case of a left-handed person is such that very slight effort is necessary to enable him to use the pen freely with it. An apt illustration of this has been communicated to me by the manager of one of the Canadian banks. He had occasion to complain of the letters of one of his local agents as at times troublesome to decipher, and instructed him in certain cases to dictate to a junior clerk who wrote a clear, legible hand. The letters subsequently sent to the manager, though transmitted to him by the same agent, presented in signature, as in all else, a totally different caligraphy. The change of signature led to inquiry; when it turned out that his correspondent was left-handed, and by merely shifting the pen to the more dexterous hand, he was able, with a very little practice, to substitute for the old cramped penmanship an upright, rounded, neat, and very legible handwriting.
In reference to the question of hereditary transmission, the evidence, as in the case of Dr. Rae, is undoubted. Dr. R. A. Reeve, in whom also the original left-handedness has given place to a nearly equal facility with both hands, informs me that his father was left-handed. Again Dr. Pye-Smith quotes from the Lancet of October 1870 the case of Mr. R. A. Lithgow, who writes to say that he himself, his father, and his grandfather have all been left-handed. This accords with the statement of M. Ribot in his Heredity. “There are,” he says, “families in which the special use of the left hand is hereditary. Girou mentions a family in which the father, the children, and most of the grand-children were left-handed. One of the latter betrayed its left-handedness from earliest infancy, nor could it be broken off the habit, though the left hand was bound and swathed.” Such persistent left-handedness is not, indeed, rare. In an instance communicated to me, both of the parents of a gentleman in Shropshire were left-handed. His mother, accordingly, watched his early manifestations of the same tendency, and employed every available means to counteract it. His left hand was bound up or tied behind him; and this was persevered in until it was feared that the left arm had been permanently injured. Yet all proved vain. The boy resumed the use of the left hand as soon as the restraint was removed; and though learning like others to use his right hand with facility in the use of the pen, and in other cases in which custom enforces compliance with the practice of the majority, he remained inveterately left-handed. Again a Canadian friend, whose sister-in-law is left-handed, thus writes to me: “I never heard of any of the rest of the family who were so; but one of her brothers had much more than the usual facility in using both hands, and in paddling, chopping, etc., used to shift about the implement from one hand to the other in a way which I envied. As to my sister-in-law, she had great advantages from her left-handedness. She was a very good performer on the piano, and her bass was magnificent. If there was a part to be taken only with one hand, she used to take the left as often as the right. But it was at needlework that I watched her with the greatest interest. If she was cutting out, she used to shift the scissors from one hand to the other; and would have employed the left hand more, were it not that all scissors, as she complained, are made right-handed, and she wished, if possible, to procure a left-handed pair. So also with the needle, she used the right hand generally; but in many delicate little operations her habit was to shift it to the left hand.”
In those and similar cases, the fact is illustrated that the left-handed person is necessarily ambidextrous. He has the exceptional “dexterity” resulting from the special organic aptitude of the left hand, which is only paralleled in those cases of true right-handedness where a corresponding organic aptitude is innate. Education, enforced by the usage of the majority, begets for him the training of the other and less facile hand; while by an unwise neglect the majority of mankind are content to leave the left hand as an untrained and merely supplementary organ. From the days of the seven hundred chosen men of the tribe of Benjamin, the left-handed have been noted for their skill; and this has been repeatedly manifested by artists. Foremost among such stands Leonardo da Vinci, skilled as musician, painter, and mathematician, and accomplished in all the manly sports of his age. Hans Holbein, Mozzo of Antwerp, Amico Aspertino, and Ludovico Cangiago, were all left-handed, though the two latter are described as working equally well with both hands. In all the fine arts the mastery of both hands is advantageous; and accordingly the left-handed artist, with his congenital skill and his cultivated dexterity, has the advantage of his right-handed rival, instead of, as is frequently assumed, starting at a disadvantage.
CHAPTER X
CONFLICT OF THEORIES
It now remains to consider the source to which the preferential use of the right hand is to be ascribed. The dominant influence of the one cerebral hemisphere in relation to the discharge of nerve force to the opposite side of the body is a fact which is now familiar to the physiologist, and the influence of the left cerebral hemisphere on the action of the right hand has already been alluded to. But this extremely probable source of right-handedness long eluded inquirers, as will be seen from a résumé of the various hypotheses suggested by eminent anatomists and physiologists. A very slight consideration of the evidence already adduced in proof of the same prevalent usage from earliest times precludes the idea of its origin in any mere prescribed custom, enforced and developed by education into a nearly universal habit. This becomes the more manifest when it is traced back to primæval races; found incorporated in ancient and modern, savage and civilised languages, and uncontroverted by any evidence calculated to discredit the indications that it was a characteristic of palæolithic and neolithic man.
The inevitable conclusion forced on the inquirer is that the bias in which this predominant law of dexterity originates must be traceable to some specialty of organic structure. On this assumption one feature in the anatomical arrangement of the most important vital organs of the body presents such a diversity in their disposition as would seem to offer a sufficient cause for greater energy in the limbs on one side than on the other, if accompanied by exceptional deviations from the normal condition corresponding to the occurrence of left-handedness; and in this direction a solution has accordingly been sought. The bilateral symmetry of structure, so general in animal life, seems at first sight opposed to any inequality of action in symmetrical organs. But anatomical research reveals the deviation of internal organic structure from such seemingly balanced symmetry. Moreover, right or left-handedness is not limited to the hand, but partially affects the lower limbs, as may be seen in football, skating, in the training of the opera-dancer, etc.; and eminent anatomists and physiologists have affirmed the existence of a greater development throughout the whole right side of the body. Sir Charles Bell says: “The left side is not only the weaker, in regard to muscular strength, but also in its vital or constitutional properties. The development of the organs of action and motion is greatest upon the right side, as may at any time be ascertained by measurement, or the testimony of the tailor or shoe-maker.” He adds, indeed, “Certainly this superiority may be said to result from the more frequent exertion of the right hand; but the peculiarity extends to the constitution also, and disease attacks the left extremities more frequently than the right.”
With the left-handed, the general vigour and immunity from disease appear to be transferred to that side; and this has naturally suggested the theory of a transposition of the viscera, and the consequent increase of circulation thereby transferred from the one side to the other. But the relative position of the heart is so easily determined in the living subject, that it is surprising how much force has been attached to this untenable theory by eminent anatomists and physiologists. Another and more generally favoured idea traces to the reverse development of the great arteries of the upper limbs a greater flow of blood to the left side; while a third ascribes the greater muscular vigour directly to the supply of nervous force dependent on the early development of the brain on one side or the other.
So far as either line of argument prevails, it inevitably leads to the result that the preference of the right hand is no mere perpetuation of convenient usage, matured into an acquired, or possibly an hereditary habit; but that it is, from the first, traceable to innate physical causes. This, as Sir Charles Bell conceives, receives confirmation from the fact already referred to, that right or left-handedness is not restricted to the hand, but affects the corresponding lower limb, and, as he believes, the whole side; and so he concludes thus: “On the whole, the preference of the right hand is not the effect of habit, but is a natural provision; and is bestowed for a very obvious purpose.” Nevertheless, the argument of Sir Charles Bell is, as a whole, vague, and scarcely consistent. He speaks indeed of right-handedness as “a natural endowment of the body,” and his reasoning is based on this assumption. But much of it would be equally explicable as the result of adaptations following on an acquired habit. Its full force will come under consideration at a later stage. Meanwhile it is desirable to review the various and conflicting opinions advanced by other inquirers.