Volume 1
The physiological anatomy and physiology of man / by Robert Bentley Todd and William Bowman.
- Date:
- 1845-1856
Licence: Public Domain Mark
Credit: The physiological anatomy and physiology of man / by Robert Bentley Todd and William Bowman. Source: Wellcome Collection.
Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.
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![reply when addressed, and resume the waking state,—the power which many unquestionably have of limiting the duration of sleep to a predetermined period, as contrasted with the deep uncon- sciousness and slowness to awake of others,—strongly favour this idea. This state, with which the revolution of each diurnal period makes us familiar as one of repose to the great centres of mental nervous actions—“tired Nature's sweet restorer”—occurs, with modifications, as the result of certain morbid processes, as the ef- fect of certain physical agents, or even as the consequence of pecu- liar states of mind. Thus, under the influence of pressure, from a clot of blood compressing the brain, or from lymph or fluid at its base, a state varying from that of drowsiness up to the profound- est sleep, or coma, may be induced. Whatever be the nature of the compressing substance, or wherever sstuate, if the hemispheres experience general pressure, this result will ensue. Again, a class of drugs, of the sedative or narcotic kind, exerts a similar influence; and, if given in too large a doss', Mill paralyse the brain. We have daily evidence of this iu the effects of opium, which para- lyses at first the centres of mental actions, and ultimately those of physical actions. Lastly, particular states of the system, in- duced, perhaps, by deranged assimilation, or by great previous dis- turbance of mind, dis]K>se persons to fall into that state which is called somnambulism. The somnambulist is one who dreams, and acts iu his dream as if he were aM-ake, and as if all the phenomena presented to him were real. He appears to the bystanders in a deep sleep, but acts with wonderful precision, walks with steady gait, and avoids obstacles. Yet frequently accidents, injurious or even fatal, occur ; which shew that on such occasions he is asleep, and has not the full command of his senses. Persons in this state Mill ansM-er questions rationally and with readiness, and do not appear to be at all disturbed by being questioned. The hypochon- driacal or hysterical diathesis disposes greatly to the developcment of somnambulism both in male and female. A state remarkably analogous to this of somnambulism may be induced in persons of nervous temperament, wdiieh has been called the Mesmeric slesp, or trance. It requires for its production the apparent influence of another individual, who watches the person experimented on with an intent look, and makes certain movements before him, which are called passes. All persons are not susceptible of passing into this state, any more than they are of exhibiting the phenomena of somnambulism. The same state of constitution which](https://iiif.wellcomecollection.org/image/b28043327_0001_0393.jp2/full/800%2C/0/default.jpg)
