DEXTRALITY AND SINISTRALITY. 369 



Almost the only letters that could not he thus remodeled and bettered 

 are V, Z , X, which are little used. K and B also require some slanted 

 strokes. The others could all be made up of vertical and horizontal 

 lines. The vast majority of astigmatisms cluster about axes 90° or 

 180°, and those which are anomalous and unsymmetric produce dis- 

 ease unless corrected, as they may be by proper spectacles. 



The summary of the foregoing theory of the origin of dextralitv 

 and sinistrality is : 



Modern pathology has demonstrated that the intellectual acts of 

 writing and reading locate the speech center upon the cerebral side 

 opposite the writing hand. 



The centers for vision, audition, and motion of the hand and foot 

 for correlated dextral or sinistral actions and sensations, are in the 

 same side of the brain. 



Coordination of sensation, perception, judgment and act are ren- 

 dered more accurate, expert and quick by this close contiguity and 

 inter-relationship than if made by commissural fibers from the other 

 cerebral hemisphere. 



The original location of the speech center in the dextral was caused 

 by the almost universal employment of the right or spear-hand in 

 sign-language preferred to the left or shield-hand, because this was 

 more restricted in movement by holding the shield over the heart. 



The origin of left-handedness was in large measure due to the loca- 

 tion or education of the speech center in the right brain because of 

 injury to dextral organs, but chiefly to disease or deficient vision of the 

 right eye. 



Ambidexterity of any general or thoroughgoing kind is neither 

 possible nor desirable, and the attempt to bring it about results in 

 suffering and disease. 



Vertical handwriting, and printed letters made up of vertical and 

 horizontal lines, should be encouraged. 



VOL. LXV. — 24. 



