A correspondent of _Nature_ (9th June 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 abnormality, 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 cognisance; 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-handedness shows that it is no necessary source of deviation from normal action.