THE ORIGIN OF RIGHT-HANDEDNESS. 615 



teen a form of unilateral stimulation wliicli would act to effect a 

 structural change in one hemisphere over and above the other. 

 But, apart from this, there is every reason to expect, quite inde- 

 pendently of function, that two organs of such comparative sep- 

 arateness and independence of function would not remain exactly 

 balanced in function ; in short, spontaneous variations giving 

 advantageous dextrality would inevitably arise and persist as soon 

 as the habits of life were not such that more important functions, 

 such as locomotion, tended to suppress them and restore bilateral 

 equilibrium.* There are, as far as I know, very few published ob- 

 servations of fact in regard to simian or animal dextrality. f 



It is likely, therefore, that right-handedness in the child is due 

 to differences in the two half-brains, reached at an early stage in 

 life, that the promise of it is inherited, and that the influences of 

 infancy have little effect upon it. Yet, of course, regular habits 

 of disuse or of the cultivation of the other hand may, as the child 

 grows up, diminish or destroy the disparitj^ between the two. 

 And this inherited brain-onesidedness also accounts for the asso- 

 ciation of right-handedness and speech the speech function being 

 a further development of the same unilateral potency for move- 

 ment found first in right or left handedness. 



The Marquis of Salisbury has been nominated as president of the next meet- 

 ing of the British Association, which will be held in Oxford, August 8th. In 

 proposing him, Sir F. Bramwell mentioned, as among the claims of the marquis, 

 that he had been Chancellor of the University of Oxford since 1880, that he 

 would therefore represent both hosts and guests, that he was a distinguished 

 statesman, a courteous gentleman, a member of the Council of the Royal Society, 

 and a true man of science. Ipswich has been designated as the place for the 

 meeting of 1895. 



* It is on this point that I differ from Wilson, who claims that while some are natu- 

 rally right or left handed, most people owe the peculiarity to education ; the evidence, apart 

 from my experiments, is well put by Mazel, toe. cit. 



f I know only the assertion of Vierordt that parrots grasp and hold food with the left 

 claw, that lions strike with the left paw, and his quotation from Livingstone i. e., "All 

 animals are left-handed" (Vierordt, loc. cit., p. 428). Dr. W. Ogle reports observations on 

 parrots and monkeys in Trans. Royal Med. and Chirur. Society, 1871. Dr. Ogle informs 

 me in a private letter that the chimpanzee which recently died in the Zoological Garden in 

 London was discovered by him to be left-handed. I have addressed a circular letter to some 

 of the officials in zoological institutions here and abroad, and hope to gather some facts in 

 this way. It is evident that on this theory of spontaneous variation any change which pro- 

 duced a permanent organic superiority of one hemisphere would be sufficient, and the view 

 that the difference in the hemispheres is due to a better blood supply to the left hemisphere 

 might thus have its justification. As a matter of fact, the arterial arrangements do seem 

 to indicate a more direct blood supply to the left hemisphere (cf. the note of Dr. J. T. 

 O'Connor, apropos of my experiments, in Science, xvi, 1890, p. 3a 1). It is an interesting 

 inquiry whether this arterial arrangement is reversed in left-handed persons. Wilson cites 

 two cases in which there was no such correspondence {loc. cit., p. 179). 



