The Right Hand by Daniel Wilson — Read

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 primeval 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 paleolithic 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."