202 EIQHTHANDEDNESS. 



from this cause must be more frequently produced in the right side 

 than the left, owing to its being more frequently used. But the venous 

 circulation on the left side is retarded by the pulsation of the aorta, and 

 therefore the more frequent motions of the right side were intended to 

 render the circulation of the two sides uniform." The idea, if correctly 

 reported, is a curious one, as it traces righthandedness to the excess of 

 a compensating force for an assumed inferior circulation pertaining 

 naturally to the right side. 



Professor Hyrtl, of Vienna, another celebrated anatomist, discusses 

 the subject in his Handhuck der TopograpJiischen Anaiomie (1860), 

 and affirms a correspondence between the ratio of left-handed persons 

 and the°occurrence of certain deviations from the normal arrangements 

 of the blood-vessels. " It happens," he says, '' in the proportion of 

 about two in a hundred cases, that the left subclavian artery has its 

 origin before the right, and in these cases lefthandedness exists, as it 

 also often actually does in the case of complete transposition of the 

 internal organs ; and it is found that the proportion of left-handed to 

 right-handed persons is also about two to one hundred." Prof Hyrtl 

 thinks that ordinarily the blood is sent into the right subclavian under 

 a greater pressure than into the left, on account of the relative position 

 of these vessels, that in consequence of the greater supply of blood, the 

 muscles are better nourished and stronger, and that therefore the right 

 extremity is more used. In cases of anomalous origin of the left sub- 

 clavian, &c., the reverse occurs, and therefore the left hand is employed 

 in preference." The theory of Professor Hyrtl has this feature to 

 recommend it, that it equally accounts for the prevalent righthanded- 

 ness, and the exceptional lefthandedness; nor can any solution of the 

 inquiry, founded on organic structure, prove satisfactory which fails to 

 do so. But the statistics of such internal organic structure, and its 

 corelation with a corresponding abnormal action, are nearly inaccessible. 

 With rare exceptions, it lies wholly beyond observation in the living 

 subject ; and any relation between it'-and the vital actions of individuals 

 thus affected, are unknown. So far, however, as ascertained facts can 

 be appealed to, they fail to sustain the above theory. 



The late eminent anatomist, Professor G-ratiolet, sought for a solution 

 of the difficulty in another direction. He maintained that in the early 

 stages of foetal development, the anterior and middle lobes of the brain 

 on the left side were in a more advanced condition than those on the 

 right side, the balance being maintained by an opposite condition of 



