362 POPULAR SCIENCE MONTHLY. 



ized man; (2) in the secondary meaning of the word sinister — unlucky, 

 ill-omened, evil; (3) in the persistent training of all left-handed 

 children, by parents, teachers, etc., to make them like the rest of the 

 right-handed world. These three facts, the residue of the psychologic 

 habits of ages, persistent in all history, crystallized and embedded in 

 the very language itself which chronicles all mentality, help to give 

 us the clue to the solution of the riddle. 



Skillfulness, 'handiness,' expertness of sense and act, were the sole 

 means whereby the savage could win his place in the world, domesticate 

 animals, conquer in all sorts of conflicts, supply himself with food, 

 clothing, house, etc. It was necessary that one hand should be chosen 

 to do the dextrous or more skilled tasks, for the simple reason that 

 exercise develops and perfects function, and one would learn to be 

 more skilled and 'handy' with one hand than with both. The savage 

 required no treatise on logic nor even any conscious reasoning to teach 

 him this primary lesson. His food and life depended upon his learn- 

 ing it. 



But that it was an acquirement, that the law and necessity were not 

 exceptionless, that it was due to no absolute fatalism of anatomy or 

 physiology, is evident from the fact that so large a proportion of left- 

 handed children and adults exist in all races and times. The educa- 

 tion of left-handed children, whereby their writing center, naturally 

 dextrocerebral, is by forced training and long habit transferred to the 

 left cerebral hemisphere, is another demonstration that no inherent 

 neurologic or psychologic law governs the location of the cerebral 

 center or its peripheral outworking. When the occasions arose in the 

 humanization process, and the demand for the differentiation of cerebral 

 mechanisms was made, the plastic brain on either side could take up 

 the work. And pure, or untrained, left-handed persons are to-day as 

 expert as their right-handed fellows. All that is needed to explain 

 dextrality in 98 per cent, of children is some ancestral savage custom, 

 habit, or necessity, widely prevalent, which inclined to the use of the 

 right hand and eye for one or two exceptionally intellectual tasks. 

 The inheritance of aptitude, the force of custom, and the necessities 

 of the struggle for existence would certainly fix the persistence of 

 dextrality. 



We must not forget that the somewhat sudden and clear preference 

 of dextrality and sinistrality of the child of to-day was in the far-away 

 ancestral line spread out over long periods of time. A year or two of 

 the child's life represents thousands of years of slow acquirement and 

 habit. 



Again, it should be remembered that even in our preferences and 

 habits it is only in a few things that one hand, etc., has the greater 

 expertness, accuracy and rapidity. It is often rather a division of 



