Page:Popular Science Monthly Volume 65.djvu/372

368, leukoma, etc., of the right eye, compelling the use of the left, and thus transferring all centers of dextrousness to the right side. I have repeatedly demonstrated the persistence of dextrocularity even with visual acuteness considerably less than that of the left. But there is a limit to this 'accommodation,' and if the amblyopia of the right is greater than double that of the left, the patient becomes left-eyed. In savage and in semicivilized life these accidents, diseases, ametropias, heterophorias and strabismuses of the right eye would again be far more numerous than in our day and civilized peoples. Our two per cent, of sinistral children seem for the greater part to be the descendants, by the laws of heredity, of ancestors who in childhood and youth have been compelled to become sinistral by the causes enumerated.

Is it possible that there are proportionally more left-handed among oriental nations who read from right to left, than in those who read from left to right? A writer in the Cornhill Magazine (1889) says that the change in writing whereby the proceeding from right to left was reversed was due to the use of ink and pigments in writing, and the avoidance of smearing the fresh-writing by tracing the letters from left to right. But individual writers would not do this, and, if they did, they could not get their writing accepted! It is difficult to see how there would be less smudge and smear by the reversal.

The arguments for upright writing are incontestably strengthened by some facts I have lately discovered as to the frequent influence of an axis of astigmatism in the dominant eye varying by about 15° from 90°, in producing a habitual canting or sideways inclination of the head. This habitual cant of the head is often followed by spinal curvature. Probably most spinal curvatures are produced in this way, and the number of cases is much greater than is supposed. Such a patient can see upright lines, which predominate over all others in civilized life, especially in those who read much, only by holding the head to one side. When the axis of astigmatism is about 75° the head must be canted to the right to see plainly. When it is 105° it must be canted to the left. Slanted handwriting is itself pathologic, or produces pathologic results of many kinds. The printed letters of the alphabet should be refashioned to avoid all lines except the vertical and horizontal. This would greatly conduce to lessening of ocular and neurologic labor, and would increase ease and celerity of reading.