thus acquired, I may add that I find no difficulty in drawing at the same time with a pencil in each hand, profiles of men or animals facing each other. The attempt to draw different objects, as a dog’s head with the one hand and a human profile with the other, is unsuccessful, owing to the complex mental operation involved; and in this case the co-operation is apt to be between the mind and the more facile hand. In the simultaneous drawing of reverse profiles there is what, to an ordinary observer, would appear to be thorough ambidexterity. Nevertheless, while there is in such cases of ambidexterity, characteristic of most left-handed persons, little less command of the right hand than in those exclusively right-handed, it is wholly acquired; nor, in my own experience, has the habit, fostered by the practice of upwards of seventy years, overcome the preferential use of the other hand. When attending the meeting of the American Association for the Advancement of Science held at Buffalo in 1867, my attention was attracted by the facility with which Professor Edward S. Morse used his left hand when illustrating his communications by crayon drawings on the blackboard. His ability in thus appealing to the eye is well known. The Boston _Evening Transcript_, in commenting on a course of lectures delivered there, thus proceeds: “We must not omit to mention the wonderful skill displayed by Professor Morse in his blackboard drawings of illustrations, using either hand with facility, but working chiefly with the left hand. The rapidity, simplicity, and remarkable finish of these drawings elicited the heartiest applause of his audience.” Referring to the narrative of my own experience as a naturally left-handed person subjected to the usual right-hand training with pen, pencil, knife, etc., Professor Morse remarks in a letter to me: “I was particularly struck by the description of your experiences in the matter, for they so closely accord with my own: my teachers having in vain endeavoured to break off the use of the left hand, which only resulted in teaching me to use my right hand also. At a short distance, I can toss or throw with the right hand quite as accurately as I can with my left. But when it comes to flinging a stone or other object a long distance, I always use the left hand as coming the most natural. There are two things which I cannot possibly do with my right hand, and that is to drive a nail, or to carve, cut, or whittle. For several years I followed the occupation of mechanical draughtsman, and I may say that there was absolutely no preference in the use of either hand; and in marking labels, or lettering a plan, one hand was just as correct as the other.” I may add here that in my own case, though habitually using the pen in my right hand, yet when correcting a proof, or engaged in other disconnected writing, especially if using a pencil, I am apt to resort to the left hand without being conscious of the change.