Page:Popular Science Monthly Volume 10.djvu/485

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In all these experiments it should be observed there is no one muscle, there is no single group of muscles, through which this tension and relaxation are developed; it is the finger, the hand, the arm, or the whole body, according to the method employed. Among the various methods of making connection between the subject and operator are the following:

1. The back of the subject's hand is held firmly against the forehead of the operator, who, with his other hand, lightly touches the fingers of the subject's hand. (Brown.)

This is, undoubtedly, the most artistic of all known methods.

2. The hand of the operator loosely grasps the wrist of the subject. This is a very inartistic method, and yet great success is oftentimes attained by it.

3. One finger of the operator is applied to one finger of the subject, papillæ touching papillæ.

This is a modification of the first method; by it exceedingly small objects or localities are found.

4. The operator is connected in the usual way with a third party who does not know the locality thought of by the subject, but is connected with the subject by the wrist ("double test").

In this experiment, which astounded even the best observers, the unconscious muscular motion was communicated from the subject to the arm of the third party, and through the arm of the third party to the operator.

5. Two, three, or more subjects, who agree on the locality to be thought of, apply their hands to the body of the operator in front and behind.

This method is excellent for beginners, and the direction is easily found by it; but it is obviously not adapted for the speedy finding of small objects; it is frequently used by ladies.

6. The hand of the subject lightly rests on the shoulder of the operator.

    and kindred disorders; namely, that the thought, the conscious mental conception, of an act, differs from the voluntary impulse necessary to the performance of that act only in that it corresponds to a fainter excitation of nervous centres in the cortex cerebri, which in both cases are anatomically identical.


    "Thus, in certain forms of aphasia the power to think in words is lost at the same time with the power of speech. Some persons think definitely only when they think aloud, and it would readily be believed in the case of children and uneducated persons that the ability to read would often be seriously interfered with if they were not permitted to read aloud. Similarly, a half-premeditated act of any kind slips often into performance before its author is aware of the fact. Further, there is reason to think, from the experiments of Hitzig, that these same centres may be excited by the stimulus of electricity so as to call out some of the simpler coordinated movements of the muscles on the opposite side of the body.


    "Applying, now, this principle to the case in hand, it will be evident that for the person experimented with to avoid giving 'muscular hints,' of either a positive or a negative kind, would be nearly impossible."