468 THE POPULAR SCIENCE MONTHLY. 



4. The uncertainty and capriciousness of these experiments, 

 even with expert operators, harmonize with the explanation here 

 given. Even with good subjects all mind-readers do not uniformly 

 succeed ; there is but little certainty or precision to the average 

 results of experiments, however skillfully performed. An evening's 

 exhibition may be a series of successes or a series of failures according 

 to the character of the subjects ; and even in the successful tests the 

 operator usually must try various directions and many localities, 

 sometimes for ten or fifteen minutes, before he finds the locality 

 sought for; cases where the operator goes at once in the right direc- 

 tion, stops at the right locality, and knoics when he has reached it, 

 are exceptional. 1 



5. Many of those who become expert in this art are aware that 

 they succeed by detecting slight muscular tension and relaxation on 

 the part of the subject. 



Some operators have studied the subject scientifically, and are 

 able to analyze with considerable precision the different steps in the 

 process. In the minds of many this fact alone is evidence adequate 

 to settle the question beyond doubt. 



6. A theoretical and explanatory argument js derived from the 

 recent discovery of motor centres in the cortex of the brain. 



I was repeating the experiments of Fritsch and Hitzig at the time 

 when my attention was first directed to the remarkable exhibitions 

 of Brown, and the results of my studies in the electrical irritation of 

 the brains of dogs and rabbits suggested to me the true explanation 

 of mind-reading before any opportunity had been allowed for satis- 

 factory experiments. 



The motto " when we think we move," which I have sometimes 

 used to illustrate the close and constant connection of mind and body, 

 seems to be justified by these experiments on the brain, and may 

 assist those who wish to obtain a condensed statement of the physi- 

 ology of mind-reading. Taking into full consideration the fact that 

 all physiologists are not in full accord as to the interpretation to be 

 given to these experiments, whether, for example, the phenomena are 

 due to direct or reflex action, still it must be allowed, by all who 

 study this subject experimentally, that thought-centres and muscle- 

 centres are near neighbors, if not identical." 



1 The popular theory to account for these failures is the weariness or exhaustion of 

 the operator ; but both in New York and in New Haven it was observed that Brown met 

 with his most brilliant successes in the latter part of the evening, the reason being that 

 he happened then to have better subjects. 



2 From an editorial in the Boston Medical and Surgical Journal (September 23, 1875), 

 referring to the mind-reading exhibitions, and accepting the explanation here given, I 

 make the following extract : 



" The whole performance seems to us to furnish good illustrations of one or two well- 

 known principles of great physiological interest. Of these the most important is one 

 that finds at once support and application in the modern doctrine of the nature of aphasia 



