34 DANIEL WILSON ON THE RIGHT 
notice, in which the entire transposition of the viscera coexisted with left-handedness. 
But he had already adopted the mechanical theory, subsequently modified, as explained 
above; and it is only in a closing remark in his paper of 1862 that he makes a passing 
reference to this remarkable coincidence. 
Professor Hyrtl, of Vienna, the eminent anatomist already referred to, in discussing 
the cause of left-handedness in his ‘‘ Handbuck der Topographischen Anatomie” (1860), 
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 left-handedness 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.” Professor 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 subclavian, etc., the reverse occurs, and therefore the left 
hand is employed in preference. The theory of Professor Hyrtl has this feature to recom- 
mend it, that it assigns a cause for the prevalent habit, which, if confirmed, would equally 
account for the exceptional left-handedness; and no proffered solution of the question, 
founded on organic structure, is deserving of attention which fails to do so. But the 
statistics of such internal organic structure are not, like those of the transposition of the 
heart and immediately related organs, accessible in the living subject, unless in very rare 
exceptions; and the occurrence of one or two cases in which the deviation from the 
normal arrangement of the artery, or the entire transposition of the viscera, is found to 
coexist with left-handedness, may only be misleading. 
A correspondent of “Nature” (June 9, 1870) refers to a case of transposition of 
the origin of the right subclavian artery, disclosed by the occurrence of aneurism, where 
the person was ascertained to have been undoubtedly right-handed. In the following 
year an interesting article by Dr. Pye-Smith appeared in the “Guy’s Hospital Reports,” 
and was subsequently reprinted, with additions, under the title of “The connection of 
left-handedness with transposition of viscera and other supposed anatomical causes.” In 
this the author states that he found the deviation from the normal arrangement of the 
primary branches of the aorta, in which the right subclavian arises from the third part of 
the aortic arch, to occur four times in 296 dissections. As this variation, he says, “cannot 
be recognised during life, its connection with left-handedness is not easy to investigate. 
But in one case, at least, Dr. Peacock ascertained for me that the subject of this abnor- 
mality, whose heart and arteries he had examined for another purpose, was right-handed 
during life.” Any one can tell on which side his heart lies ; but the disposition of the 
subclavian artery is wholly beyond his cognizance; and, indeed, Professor Hyrtl, while 
referring to this abnormal organisation as one probable cause of left-handedness, does not 
affirm more than that the one has been ascertained in some cases to be an accompaniment 
of the other. The evidence that in other cases it has been unaccompanied by left-handed- 
ness shows that it is no necessary source of deviation from normal action. 
The other theory, that left-handedness is an inevitable accompaniment of the trans- 
