418 E. GUKNEY :

Smith's passes by currents of air, someone else made similar and simultaneous passes over another finger. But it might still be objected that some imperceptible difference in the manner of making the passes produced differences in the currents of air; and a far better method which I have employed in 20 later trials (as well as in a few of the earlier ones) is to dispense with passes altogether. Mr. Smith has held his hand perfectly still about a couple of inches over the selected finger ; and the diminution of sensi- bility, though less in degree than when passes were made, has in every case (with possibly one exception) been quite unmistakable, while in nearly all the cases the rigidity has been sufficient to prevent the finger being quickly flexed. 1 Here, then, the only means of direct perception left open seems to be warmth. Perception by this means would involve hypersesthesia in an extreme degree; and in this connexion I may mention that a scientific friend at Cam- bridge (whose results will in time, I trust, be published) tells me that he has produced similar effects, under similar con- ditions, with two sheets of glass between his hand and that of the ' subject'. But I believe that I have sufficiently guarded against the conveyance of information through warmth by holding my own hand, at the same distance as Mr. Smith's, over another of the ' subject's ' fingers. After we have been for some time together in a warm room, Mr. Smith's hand and mine do not perceptibly differ in temperature ; yet mine never produced any effect on the ' subject'. 2 Another fact of great significance is that I have now got both the ' subjects ' on whom these recent experiments have been made to attend to their sensations during the process. They used to profess unconsciousness of any change whatever; but they are now able to detect which finger has been the subject of experiment by what they describe as a slight feeling of cold. That this should be the direct effect of the proximity of someone else's warm hand seems inconceivable, especially since the feeling lasts after the hand is removed ; but it is perfectly easy to account for as a secondary result of the increasing numbness and loss of normal sensibility. It should be noted further that the effect was removed in just the same manner that is to say, the proximity of Mr. 1 In two cases the corresponding finger on the other hand, and in a third case an adjacent finger, was also slightly affected. 2 I propose in some future experiments to apply the same test when the temperature of Mr. Smith's and my hands has been distinctly lowered and raised by immersion in iced and heated water.