The human foot and the human hand

by George Murray Humphry

Cause of the preferential use of the Right Hand.

Why is man usually RIGHT-HANDED? Many attempts have been made to answer this question; but it has never been done quite satisfactorily; and I do not think that a clear and distinct explanation of the fact can be given.

There is no anatomical reason for it with which we are acquainted. The only peculiarity that we can discern is a slight difference in the disposition, within the chest, between the blood-vessels which supply the right and the left arms. This, however, is quite insufficient to account for the disparity between the two limbs. Moreover, the same disposition is observed in left-handed persons, and in some of the lower animals; and in none of the latter is there that difference between the two limbs which is so general among men.

Is the superiority of the right hand real and natural, that is, congenital? or is it merely acquired? I incline much to the latter view; because all men are not right-handed; some are left-handed; some are ambidextrous; and in all persons, I believe, the left hand may be trained to as great expertness and strength as the right‍[9]. It is so in those who have been deprived of their right hand in early life; and most persons can do certain things with the left hand better than with the right.

Nevertheless, though I think the superiority of the right hand is acquired and is a result of its more frequent use, the tendency to use it, in preference to the left, is so universal that it would seem to be natural. I am driven, therefore, to the rather nice distinction, that, though the superiority is acquired, the tendency to acquire the superiority is natural.

It may be argued that the tendency must be based upon something physical, and that, therefore, a tendency to superiority implies an actual superiority. This may be so; but I do not think that we are quite in a position to assert that it is so. We perceive that there is a tendency to the preferential use of the right hand; but we do not know upon what that tendency depends, and have, therefore no right to assert that the cause of it lies in the construction of the limb or of the parts which supply the limb with blood and nervous influence, or, indeed, upon any strictly physical cause whatever.

It may be a tendency like that of certain animals to make their holes and nests in particular places and in particular ways, to watch for their prey at particular spots, to migrate in certain directions at particular periods, and to group themselves in a particular order during their travels. Such tendencies, or “Instincts” as they are often called, may possibly be the result of a peculiar conformation of the several animals; but it is, at present, by no means certain that they are so.

I have said that man is the only animal in whom a preference in the use of the limb or limbs of one side is shown. This is a consequence of the fact that he is the only animal who has occasion to use the limbs of the two sides separately, or who is in the habit of doing so. Even in the rudest state of society this habit is engendered in him from a very early period, as in carrying a stick, throwing a spear, and in a variety of ways. The habit increases as he becomes more civilized, owing to the greater number of offices which the hands are called upon to perform; and the necessity for using the hands separately would, of itself, lead each individual to the employment of one more frequently than the other; but that that one should so universally be the right hand, seems to be accounted for only by reference to some natural tendency. The imitative propensity in man and the convenience of uniformity of modes of action are scarcely sufficient to account for it.

I will not detain you by dwelling upon the effect which the superiority of the right hand has in giving a slight superiority to the right leg and the right eye, and will content myself with mentioning a single beneficial result of the preferential use of one hand, viz. that by it, we acquire a greater degree of skilfulness and dexterity than we should do if both hands were equally employed. The exclusive use, for instance, of the right hand in writing, cutting, &c. gives it a greater expertness than either hand would have had if both of them had been accustomed to perform these offices. Hence, we usually find that persons who are left-handed are rather clumsy-fingered, because, although, in them, the left hand is used for many purposes which are commonly assigned to the right, yet the conventionalities of life interfere a good deal. The pen and the knife, for instance, are still wielded by the right hand. Accordingly such persons are neither truly right-handed nor truly left-handed; and they do not commonly acquire so great skill in the use of either hand as do those whose natural tendency is more in harmony with custom.

The great martyr of our Church, when at the stake, is said to have held out his right hand into the flames and to have been heard exclaiming, till utterance was stifled, “This unworthy hand.” This unworthy hand! Of whom or of what was that hand unworthy? Was it unworthy of Him who made it? Was it unworthy of him who bore it? Was it unworthy of the purposes for which it was made? Was it not, on the contrary, a too worthy hand? a hand worthy of a better usage than to be made, first, to sign a recantation of faith and, then, to be burned for having done so? a hand worthy of a better man? No one would have admitted this more readily than Cranmer. We may be sure that he would never have thought of proclaiming a hand or any of his members to be really unworthy of him. Rather would he have willingly confessed that he had fallen far short of the standard of excellence which the body presents; and in that excellence, we doubt not, he recognised an evidence of Divine workmanship. His meaning, therefore, has not been misunderstood. Nevertheless disparaging remarks respecting the body, and the use of the word “carnal” in the sense in which it is usually employed, have some tendency to excuse a shrinking from moral responsibilities on the ground of the weakness of the flesh. Let us remember that much of that weakness is of our own engendering, that a moral obliquity is the source of many of those physical infirmities which, we flatter ourselves, may cover our delinquencies, and which a sympathising humanity is wont, perhaps too often, to throw as a shield over offenders against the laws. In man, and in man alone of created beings, the physical and the moral grow up together and react upon one another; and the charge of a body thus capable of influencing and being influenced demands all our energies to prove ourselves worthy of it.