60 PHYSIOLOGY CHAP. 



consciousness of his own body. Probably the same phenomenon 

 takes place in insane subjects who speak of themselves in the third 

 person. All the alterations and perversions of organic sensibility, 

 of which Eibot gave a brilliant analysis in his Maladies de la 

 personnalitt, come into this group of phenomena, since coenaesthesia 

 is the physical basis of individual personality. 



Can the sensibility of the internal organs be so extended and 

 intensified that the work of the organs of vegetative life, which is 

 normally carried on unconsciously, may reach 'consciousness ? Is 

 the threshold of consciousness at a fixed and constant level, or 

 does it oscillate, and can it under certain extraordinary or abnormal 

 conditions drop so much that its range is correspondingly increased 

 and widened? This question is as important as it is delicate. 

 Reliable authors who have concerned themselves with hypnosis 

 and other similar states (Beaunis, Liebeault, and others) affirm 

 that many persons have in the hypnotic state a more or less clear 

 sense of the organic changes and of normal or morbid states that 

 occur within the organs of vegetative life. It is well authenticated, 

 according to Beaunis, that during hypnotic sleep and even in the 

 somnambulist waking state, all the functions of vegetative life caii 

 be modified by suggestion the pulse rate can be altered, redness 

 and persistent congestion can be produced in certain regions of 

 the skin, cutaneous haemorrhage can be induced, the menstrual 

 flow can be diminished, increased, or regulated, the different secre- 

 tions (tears, sweat, milk, urine, intestinal juices) can be excited or 

 arrested, uterine contractions similar to those of parturition can 

 be produced, the temperature of the skin raised, and lastly, blisters 

 formed in the skin. These surprising phenomena show that the 

 brain is able under certain conditions to transmit a centrifugal 

 effect even to the organs of vegetative life, and to affect their 

 activities as it does the muscles of animal life, and implies the 

 existence of a centripetal current from these organs to the brain, 

 by which it may receive a more or less distinct sensation of the 

 processes going on in the organs. In order, says Liebeault, to 

 explain the. suggestive action of thought on the tissues as a whole 

 during somnambulism, it is necessary to admit that the brain 

 which transmits orders to the glands, blood-vessels, etc., is aware 

 of the sensations that come from them. 



Apart from his spiritualist convictions, the posthumous work 

 of F. W. Myers on " Human Personality " contains a fund of in- 

 controvertible facts which have not yet been analysed by the 

 physiologist. Some of these observations show that the threshold 

 of consciousness is not fixed and invariable, but may alter con- 

 siderably, spontaneously or artificially, in different states of the 

 nervous system occurring in individuals who are specially pre- 

 disposed or trained by special education. 



III. From the practical point of view the commonest and 



