FUETHEB PEOBLEMS OF HYPNOTISM. (l.) 215

stimulus. No doubt a favourable attitude of mind on the part of an exceptionally sensitive ' subject ' may so prepare the organism, and the physical stimulus that supervenes may be of so simple and ordinary a kind, that its essential part in the result is liable to be overlooked. Thus it is said of certain French ' subjects ' that a moment's fixation of attention, followed by a command to sleep, has proved effec- tive even on a first occasion ; and it may then seem reason- able to refer the change of state to the mere idea of sleep, or to the expectancy of a sudden change as soon as the com- mand was given. But the idea of sleep had been present for some time, without the effect being produced ; I, at any rate, know of no instance where precautions were taken to keep the ' subject ' entirely ignorant of the intended trial up to the moment that it was made. And if it were enough to be expectant of a sudden change when the command came, the change ought equally to supervene if the operator gave his command silently, e.g., by means of the ' dumb alphabet '. Till some such case is recorded, we seem justified in attribu- ting this sudden change to the suddenly presented new element i.e., the arresting sound of the operator's voice. When the

• subject ' is of a specially unstable constitution, the condi-

tion of expectancy may be wholly dispensed with, and a rather stronger stimulus a distinct shock will then be necessary ; but always of a physical sort. The mental shock of surprise or terror may, as we all know, produce temporary paralysis of motor power and other physical effects ; but the only shocks which have been followed by the characteristic phenomena of hypnotic trance have been those due to a sudden loud sound or sudden bright light. It is worth re- marking, by the way, that the state produced in this way is always that of catalepsy, not that of lethargy, which is the more common first stage of hypnotism. The difference between these two states has, I believe, been considerably exaggerated by the school of the Salpetriere ; but so far as they really differ, it is of interest that the direct production of either should equally lead on to that unbalanced but potentially active mental condition in which the character- istic somnambulic phenomena present themselves. For this suggests that the unbalancing depends not so much on the special nature as on the suddenness of the change ; and that the somnambulic phenomena may be liable to appear after any very rapid shifting of the level of consciousness, which does not, like ordinary sleep, sink the reason below the point where attention can be attracted to imposed hallucinations and commands, and which is not, like the passage into