peculiarity of organization rendering it easy, it is never acquired. In ordinary circumstances the number of those who can write with their toes is extremely rare, the urgent necessity which would create such a power being rare; and rare also are the examples of those who have any control over the movement of the iris, or the action of a gland; but both rarities exist. It would be difficult to choose a more striking example of reflex action than the contraction of the iris of the eye under the stimulus of light;[214] and to ordinary men, having no link established which would guide them, it is utterly impossible to close the iris by any effort. It would be not less impossible to the hungry child to get on the chair and reach the food on the table, until that child had _learned_ how to do so. Yet there are men who have learned how to contract the iris. The celebrated Fontana had this power; which is possessed also by a medical man now living at Kilmarnock--Dr. Paxton--a fact authenticated by no less a person than Dr. Allen Thomson.[215] Dr. Paxton can contract or expand the iris at will, without changing the position of his eye, and without an effort of adaptation to distance. To move the ears is impossible to most men. Yet some do it with ease, and all could learn to do it. Some men have learned to “ruminate” their food; others to vomit with ease; and some are said to have the power of perspiring at will.[216] Now, if once we recognize a link of sensation and motion, we recognize a possible source of control; and if the daily needs of life were such that to fulfil some purpose the action of the heart required control, we should learn to control it. Some men have, without such needs, learned how to control it. The eminent physiologist, E. F. Weber of Leipzig, found that he could completely check the beating of his heart. By suspending his breath and violently contracting his chest, he could retard the pulsations; and after three or five beats, unaccompanied by any of the usual sounds, it was completely still. On one occasion he carried the experiment too far, and fell into a syncope. Cheyne, in the last century, recorded the case of a patient of his own who could at will suspend the beating of his pulse, and always fainted when he did so.