i. p. 39: 1 quote from the 3rd edit. revised by Prof. Turner, 1870, p. 28. See, also, Gratiolet, De la Phys. pp. 283-287.
[34] De la Phys. p. 283.
It is generally believed that the peristaltic movements of the intestines are influenced by attention being paid to them at fixed recurrent periods; and these movements depend on the contraction of unstriped and involuntary muscles. The abnormal action of the voluntary muscles in epilepsy, chorea, and hysteria is known to be influenced by the expectation of an attack, and by the sight of other patients similarly affected.[37] So it is with the involuntary acts of yawning and laughing.
Certain glands are much influenced by thinking of them, or of the conditions under which they have been habitually excited. This is familiar to every one in the increased flow of saliva, when the thought, for instance, of intensely acid fruit is kept before the mind." It was shown in our sixth chapter, that an earnest and long-continued desire either to repress, or to increase, the action of the lacrymal glands is effectual. Some curious cases have been recorded in the case of women, of the power of the mind on the mammary glands; and still more remarkable ones in relation to the uterine functions.[39]
[35] `Chapters on Mental Physiology,' 1858, p. 111. [36] `Mind find Brain,' vol. ii. 1860, p. 327. [37] `Chapters on Mental Physiology,' pp. 104-106. [38] See Gratiolet on this subject, De la Phys. p. 287. [39] Dr. J. Crichton Browne, from his observations on the insane, is convinced that attention directed for a prolonged period on any part or organ may ultimately influence its capillary circulation and nutrition. He has given me some extraordinary cases; one of these, which cannot here be related in full, refers to a married woman fifty years of age, who laboured under the firm and long-continued delusion that she was pregnant. When the expected period arrived, she acted precisely as if she had been really delivered of a child, and seemed to suffer extreme pain, so that the perspiration broke out on her forehead. The result was that a state of things returned, continuing for three days, which had ceased during the six previous years. Mr. Braid gives, in his `Magic, Hypnotism,' &c., 1852, p. 95, and in his other works analogous cases, as well as other facts showing the great influence of the will on the mammary glands, even on one breast alone.
When we direct our whole attention to any one sense, its acuteness is increased;[40] and the continued habit of close attention, as with blind people to that of hearing, and with the blind and deaf to that of touch, appears to improve the sense in question permanently. There is, also, some reason to believe, judging from the capacities of different races of man, that the effects are inherited. Turning to ordinary sensations, it is well known that pain is increased by attending to it; and Sir B. Brodie goes so far as to believe that pain may be felt in any part of the body to which attention is closely drawn.[41] Sir H. Holland also remarks that we become not only conscious of the existence of a part subjected to concentrated attention, but we experience in it various odd sensations. as of weight, heat, cold, tingling, or itching.[42]
Lastly, some physiologists maintain that the mind can influence the nutrition of parts. Sir J. Paget has given a curious instance of the power, not indeed of the mind, but of the nervous system, on the hair. A lady "who is subject to attacks of what is called nervous headache, always finds in the morning after such an one, that some patches of her hair are white, as if powdered with starch. The change is effected in a night, and in a few days after, the hairs gradually regain their dark brownish colour.[43]
[40] Dr. Maudsley has given (`The Physiology and Pathology of Mind,' 2nd edit. 1868, p. 105), on good authority, some curious statements with respect to the improvement of the sense of touch by practice and attention. It is remarkable that when this sense has thus been rendered more acute at any point of the body, for instance, in a finger, it is likewise improved at the corresponding point on the opposite side of the body.