1919] PRESIDENTIAL ADDRESS 643 In later y.ears I understand he did not often introduce the subject, foiit when questioned was firm that he had nothing to retract. One would give much to know whether this attitude is still maintained. Any hesitation that I may have felt in undertaking the honourable office to which you have called me was largely due to the fact that I have no definite conclusions to announce, and that such experiences as I have had were long ago, and can hardly now carry weight as evidence to anyone but myself. But I have always taken an interest in questions such as those considered by the Society, and I may perhaps as well give a short account of what I have seen, for it will at any rate help to explain my attitude and serve as a foundation for comment. I may begin with what is now called hypnotism. This is an old story; but many have forgotten, or never realized, the disbelief which was general in the fifties of the last century both on the part of the public and of medical men. As to the former, reference may be made to Punch*, and as to the latter I suppose there can be no doubt, although of course there were distinguished exceptions. At the present day orthodox medical opinion has so far shifted its ground as to claim for the" profession control of what was formerly dismissed as impossible and absurd—certainly a less unreasonable position. It was some ten or eleven years from the date of Punch's cartoon that I witnessed in a friend's rooms at Cambridge an exhibition of the powers of Madame Card. I think eight or ten of us were tried, including myself. We were made to gaze for a time at a " magnetic" disk; afterwards she made passes over our closed eyes, and finally defied us to open them. I and some others experienced no difficulty; and naturally she discarded us and developed her powers over those—about half the sitters—who had failed or found difficulty. Among the latter were personal friends of my own and two well-known "University athletes. One was told that he could not give his name, another that he would have to cross' the room towards her when she beckoned, and so on. In spite of obvious efforts to resist her influence they had to obey. In conversation afterwards they assured me that they could not help it; and indeed they made such fools of themselves that I had no difficulty in believing them. From that evening I have never felt any doubt as to the possibility of influencing unwilling minds by suggestion; and I have often wished that on other occasions, where dubious phenomena were in question, some of which I shall presently refer to, conviction one way or the other had followed this precedent. I ought to add that, although stories were afloat to that effect, I * Vol. xxiv. p. 120 (1853).—Lecturer on Electro-Biology. "Now, Sir! You can't jump over that Stick! Ahem !" Subject. " Jump? Eh! Ugh! Lor bless me, Jump ? No, I know I can't— never could jump—Ugh!" [Thunders of Applause from the Gentlemen in the cane-bottom chairs—(i.e. believers). 41—2iv. 38or 7? = 27rJR/X = 2 occurs when //= +-5, where /u, is the cosine of the angle between the secondary (or scattered) ray and the backward direction of the incident ray. W. F. S.]spheres are easily demonstrated.