I have cited first this experiment at a distance, without attempting to analyse the nature of the suggestion given or power employed by the hypnotist. Of course it is plain that if one can thus influence unexpectant persons from a distance there must be sometimes some kind of power actually exercised by the hypnotiser;--something beyond the mere tact and impressiveness of address, which is all that Bernheim and his followers admit or claim. Evidence of this has been afforded by the occasional production of organic and other effects in hypnotised subjects by the unuttered will of the operator when near them. The ingenious experiments of Gurney[94] in the production of local rigidity and anæsthesia were undertaken to test whether the agency employed were more in the nature of an effort of will or,--as the early mesmerists claimed,--of an emission of actual "mesmeric fluid" or physical effluence of some sort. Gurney was inclined to think that his results could not be explained solely by mental suggestion or telepathy, because the physical proximity of the operator's hand seemed necessary to produce them, and he thought it probable that they were due to a direct nervous influence, exercised through the hand of the operator, but not perceptible through the ordinary sensory channels. Mrs. Sidgwick's experiments[95] of the same kind, however, in which success was obtained when the operator was standing with folded arms several feet away from the subject, removed Gurney's main objection to the telepathic explanation. The fact that a thick sheet of glass over the subject's hands did not interfere with the results also afforded some presumption against the hypothesis of a physical influence; and Mrs. Sidgwick pointed out that the delicate discrimination involved in the specific limitations of the effects is much more easily attributable to mental suggestion, through the action of the operator's mind on that of the subject, than to any direct physical influence on the latter's nerves.