The right hand may be said to express all active volition and all beneficent action, as in Æn. vi. 370, “Da dextram misero,” “Give thy right hand to the wretched,” i.e. give him aid; and so in many other examples, all indicative of right-handedness as the rule. The only exception I have been able to discover occurs in a curious passage in the Eclogues of Stobæus Περὶ ψυχῆς, in a dialogue between Horus and Isis, where, after describing a variety of races of men, and their peculiarities, it thus proceeds: “An indication of this is found in the circumstance that southern races, that is, those who dwell on the earth’s summit, have fine heads and good hair; eastern races are prompt to battle, and skilled in archery, for the right hand is the seat of these qualities. Western races are cautious, and for the most part left-handed; and whilst the activity which other men display belongs to their right side, these races favour the left.” Stobæus, the Macedonian, belongs, at earliest, to the end of the fifth century of our era, but he collected diligently from numerous ancient authors, some of whom would otherwise be unknown; but the passage is part of a description in which he speaks of the earth as having its apex or head to the south, the right shoulder to the east, and the left to the south-west; and the left-handed races of the west may be so merely in a figurative sense. This description, at any rate, is the only indication, vague and dubious as it is, of a belief in the existence of a left-handed race.
Thus all evidence appears to conflict with the idea that the preferential employment of one hand can be accounted for by a mere general compliance with prevailing custom. Everywhere, in all ages, and in the most diverse conditions of civilised and savage life, the predominant usage is the same. Not that there are not everywhere marked exceptions to the prevailing practice, in left-handed athletes, handi-craftsmen, artificers, and artists, generally characterised by unusual dexterity; but the farther research is carried, it becomes the more apparent that these are exceptional deviations from the normal usage of humanity.
CHAPTER IX
PSYCHO-PHYSICAL ACTION
The venerable philosopher of Chelsea, musing, with sorrowful experiences to stimulate inquisitiveness, after wondering if any people are to be found barbarous enough not to have this distinction of hands, sums up with the evasion: “Why that particular hand was chosen is a question not to be settled; not worth asking except as a kind of riddle.” It seems, however, to be regarded by intelligent inquirers as a riddle that ought to be, and that can be solved, though they have wandered into very diverse courses in search of a solution.
It has been affirmed, for example, that while the right hand is more sensitive to touch, and, as it were, the special seat of the sense of feeling,—as with the right-handed it may well be from constant employment in all operations involving such a test,—the left hand is stated to be the more sensitive to any change of temperature.
Mr. George Henry Lewes, in his Physiology of Common Life, says: “If the two hands be dipped in two basins of water at the same temperature, the left hand will feel the greater sensation of warmth; nay, it will do this even where the thermometers show that the water in the left basin is really somewhat colder than in the right basin;” and he adds: “I suspect that with ‘left-handed’ persons the reverse would be found.” On the assumption that the former is a well-established law, the latter seems a legitimate inference; but, as will be seen from what follows, there is good reason for doubting that the statement rests on an adequate amount of evidence.
To determine the prevalence of this relative sensitiveness to heat of the right and left hand, the test ought to be applied to uncultured and savage, as well as to civilised man. The elements which tend to complicate the inquiry are very various. The left-handed man is nearly always ambidextrous, though with an instinctive preference for the left hand in any operation requiring either special dexterity or unusual force. Hence his right hand, though less in use than that of the right-handed man, is in no such condition of habitual inertia as the other’s left hand. Again, a large number give the preference to the right hand from a mere compliance with the practice of the majority; but with no special innate impulse to the use of one hand rather than the other. But besides those, there is a considerable minority in whom certain indications suffice to show that the bias, though no strong and overruling impulse, is in favour of the left hand. I have, accordingly, had a series of tentative observations made for me in the Physical Laboratory of the University of Toronto, under the superintendence of Mr. W. J. Loudon, Demonstrator of Physics. The undergraduates willingly submitted themselves to the requisite tests; and the series of experiments were carried out by Mr. Loudon with the utmost care. No idea was allowed to transpire calculated to suggest anticipated results. A highly characteristic Canadian test of any latent tendency to right or left-handedness was employed. In the use of the axe, so familiar to nearly every Canadian, alike in summer camping-out and in the preparation of winter fuel, the instinctive preference for one or other hand is shown in always keeping the surer hand nearest the axe-blade. This test was the one appealed to in classifying those who submitted to the following experiments. The trial was made with water very nearly 30° centigrade. The results arrived at are shown here, the persons experimented on being divided into three classes: (1) Right-handed, or those who habitually use the right hand, and who in handling an axe place the right hand above the left, nearest the axe-head. (2) Ordinarily using the right hand, but placing the left hand above the right in the use of the axe. These appear to be generally ambidextrous. (3) Those who are generally said to be left-handed, but employ the pen in the right hand, and also use that hand in many other operations. This class includes very varying degrees of bias; and though loosely characterised as left-handed, from some greater or less tendency to use that hand, the majority of them were found to place the right hand above the left in the use of the axe. One hundred and sixty-four in all were subjected to the test, with the following results: Of ninety right-handed persons, thirty-five found the right hand the more sensitive, thirty-three the left hand, and twenty-two failed to discern an appreciable difference. Of fifty-six persons of the second class, right-handed but using the left as the guiding hand with the axe, seventeen found the right hand the more sensitive, and fifteen the left, while twenty-four felt no difference. Of eighteen of the third class, six found the right hand the more sensitive, seven the left hand, and five could detect no difference. Another case was that of a lady, decidedly left-handed, who writes, sews, and apparently does nearly everything with her left hand. She tried at three temperatures, viz. 5°, 30°, and 48° centigrade. In the first case she pronounced the left hand to be undoubtedly colder, in the second she observed no difference, and in the third, the left hand was undoubtedly warmer. Another lady, also habitually using her needle in the left hand, and otherwise instinctively reverting to that hand in all operations requiring delicate or skilful manipulation, repeated the same experiment more than once at my request; but could not detect any difference in the sensitiveness of either hand. The results thus stated were all arrived at with great care. It is manifest that they fail to confirm the statement set forth in the Physiology of Common Life, or to point to any uniformity in the relative sensitiveness of the right and left hands. In so far as either hand may prove to be more sensitive to heat than the other, it is probably due to the constant exertion of the one hand rendering it less sensitive to changes of temperature. Yet even this is doubtful. Two carpenters chanced to be at work in the College building while the above experiments were in progress. They were both right-handed workmen; yet, contrary to expectation, on being subjected to the test, they both pronounced the right hand to be more sensitive to heat. The statement of Mr. Lewes is so definite that the subject may be deserving of more extended experiment under other conditions. Any widely manifested difference in the sensitiveness of one of the hands, apart from its habitual use in all ordinary manipulation, and especially among uncultured races, would assuredly seem to indicate some congenital distinction leading to the preferential use of the right hand. But whatever may be the source of this preference, the difference between the two hands is not so great as to defy the influence of education; as is seen in the case of those who, even late in life, through any injury or loss of the right hand, have been compelled to resort to the less dexterous one.
Of the occurrence of individual examples of left-handedness the proofs are ample, seemingly from earliest glimpses of life to the present time; and it would even appear that, in so far as the small yet definite amount of evidence of the relative percentage of the left-handed enables us to judge, it differs little now from what it did at the dawn of definite history.
Professor Hyrtl of Vienna affirms its prevalence among the civilised races of Europe in the ratio of only two per cent; and the number of the old Benjamite left-handed slingers, as distinguished from other members of the band of twenty-six thousand warriors, did not greatly exceed this. In the ruder conditions of society, where combined action is rare, and social habits are less binding, a larger number of exceptions to the prevailing usage may be looked for; as the tendency of a high civilisation must be to diminish its manifestation. But education is powerless to eradicate it where it is strongly manifested in early life. My attention has been long familiarly directed to it from being myself naturally left-handed; and the experience of considerably more than half a century enables me to controvert the common belief, on which Dr. Humphry founds the deduction that the superiority of the right hand is not congenital, but acquired, viz. that “the left hand may be trained to as great expertness and strength as the right.” On the contrary, my experience accords with that of others in whom inveterate left-handedness exists, in showing the education of a lifetime contending with only partial success to overcome an instinctive natural preference. The result has been, as in all similar cases, to make me ambidextrous, yet not strictly speaking ambidexterous.
The importance of this in reference to the question of the source of right-handedness is obvious. Mr. James Shaw, by whom the subject has been brought under the notice of the British Association and the Anthropological Institute, remarks in a communication to the latter: “Left-handedness is very mysterious. It seems to set itself quite against physiological deductions, and the whole tendency of art and fashion.” Dr. John Evans, when commenting on this, and on another paper on “Left-handedness” by Dr. Muirhead, expressed his belief that “the habit of using the left hand in preference to the right, though possibly to some extent connected with the greater supply of blood to one side than the other, is more often the result of the manner in which the individual has been carried in infancy.” This reason has been frequently suggested; but if there were any force in it, the results to be looked for would rather be an alternation of hands from generation to generation. The nurse naturally carries the child on the left arm, with its right side toward her breast. All objects presented to it are thus offered to the free left hand; and it is accordingly no uncommon remark that all children are at first left-handed. If their training while in the nurse’s arms could determine the habit, such is its undoubted tendency; but if so, the left-handed nurses of the next generation would reverse the process.