186 ROYAL SOCIETY OF CANADA 



and uteru?, with a testicle in tJie right vuh^im and an ovary on the left 

 f^ide. Again showing the left the weaker side. 



These cases are too few in niimbev to make any very strong state- 

 ment as to the ditïerence of frequency of deformity on the left as against 

 the right, but they do tend to show a leaning to deformities more fre- 

 quent on the left side and to a greater extent on the left side than the 

 right. 



Paralysis or hemiplegia is more frequent on the right side than on 

 the left, and in tliis case the injury to the brain is on the left side, while 

 the effect is on the right side, due to the decussation of the fibres. 



All these observations tend to the idea that the right side is a little 

 stronger than the left, and hence the use of the right hand more than 

 the left. 



The carpenter and stonemason and blacksmith, like the majority, 

 are mostly right-iianded men and they hold their chisels when they want 

 to direct the cut, in the left iiand, and strike with the heavy mallet with 

 the right hand. 



In his second article on this subject. Sir Daniel Wilson says, page 

 3, section 2, papers for 1886 : •' The phenomenon to be explained is not 

 " merely why each individual uses one hand rather than another. Ex- 

 " perience abundantly accounts for this. But if, as seems to be the case, 

 " all nations, civilized and savage, appear from remotest times to have 

 " used the same hand, it is in vain to look for the origin of this as an 

 " acquired habit. Only by referring it to some anatomical cause can its 

 " general prevalence among all races and in every age be satisfactorily 

 " accounted for. Nevertheless, this simple phenomenon cognisant to the 

 " experience of all and brought under constant notice in our daily inter- 

 " course with others, seems to balHe the physiologist in his search for any 

 " entirely satisfactory explanation." 



He goes further into the habits of man in different countries and 

 into the various reasons assigned for the predominant condition of right- 

 liandedness, by physicians, anatomists and physiologists, some giving an 

 opinion as Sir C. Bell, that not only is man right-handed, but also right- 

 footed, and that the right side is stronger than the left physically, others 

 stating that the blood supply is better to the right side than the left, 

 again that it is due to the difference in the blood supply to the brain, 

 and even to the difference in size of the two sides of the brain. 



If the course of the blood be, starting from the apex of the left 

 ventricle through the ventricle into the aorta, and then a line be drawn 

 as it were through the left ventricle and the course of the ascending 

 aorta, through the arch of the aorta, and down to the promentary of the 

 sacrum, it will be found to be represented thus, and if a plan were made 



