THE CANADIAN JOURNAL. 



NEW SERIES. 



No. XCV.— JULY, 1877.. 



LEFTHANDEDNESS. 



BY DANTEL WILSON, LL.D., F. R. S. B. 



Under the title of " Righthandedness," the specialities of this 

 common attribute of man, and the sources and characteristics of the 

 occasional deviation from it, have been discussed in. a former paper.* 

 I now propose, under the present title, to supplement it with some 

 additional suggestions and illustrations. 



If righthandedness can be referi-ed to any anatomical cause — 

 such as the position of the viscera, their relative weight on the two 

 sides of the body, the development of the subclavian arteries, or the 

 predominance of one of the cerebral hemispheres, — then its general 

 prevalence, or assumed universality, among all races and in all ages, 

 is easily accounted for ; and lefthandedness may be traced, with 

 reasonable probability, to a reversal of the normal anatomical con- 

 ditions of the body. But no theory is of any value which fails 

 to account for the exceptional lefthandedness, no less than for the 

 prevalent righthandedness. The evidence of righthandedness as a 

 predominant habit is obvious ; but its source is not yet certainly 

 determined, and acquires a fresh intex'est in so far as this natural 

 endowment or habit is peculiar to man. 



If righthandedness is referable to anatomical causes, some traces 

 of it may be looked for among mammalia generally, and especially 



* Canadian Journal, N. S., Vol. xiii., p. 193. 



