AND BODILY STATES UPON THE IMAGINATION. 225 



Perfect sleep is a state not frequently enjoyed or long continued, 

 attendant only upon the most complete bodily and mental health. 

 There is a state of mental disturbance common to sleep, in which 

 the faculties of the mind are irregularly called into action, losing 

 their proper and accustomed bearing and relation, acting indepen- 

 dently of each other, and producing combinations which rarely have 

 any existence in nature, but which are, at various times, and under 

 various circumstances, pleasing, ludicrous, or terrific. This consti- 

 tutes dreaming. Dreams, under ordinary circumstances, are not 

 sufficiently vivid in their pictures, or do not act with stimulus of 

 sufficient power upon the sensorium to induce it to call into action, 

 in a more or less isolated form, the senses, or the organs of locomo- 

 tion. In its more active and extraordinary forms we have, how- 

 ever, induced sleep-talking and sleep-walking — the Paroniria lo* 

 qitens, and the Paroniria arnbulans, of the classification of Dr. Mason 

 Good. The Iniagination of our dreams are of three distinct classes. 

 1. Those which, however vividly impressed upon the Imagination, 

 do not call into action any of the voluntary functions, i. e., any 

 power of body over which we have any coutroul when awake : 2, 

 Those which call into action one of the senses separately, under 

 which must be included speech : and 3. Those which are sufficiently 

 powerful to excite one or more of the senses in conjunction with 

 the organs of locomotion ; to cause the person so affected to go to 

 long distances, and into perilous situations, from which he returns 

 perfectly safe, in order to perform actions which, when awake, he 

 is not conscious of having committed. Sleep-talking is a modifica- 

 tion merely of somnambulism ; a variety in degree of that condition 

 of the sensorium which produces, in its more violent forms, sleep- 

 walking. Dr. Macnish supposes that '^ sleep-talking consists in a 

 distribution of sensorial power to the organs of speech, by which 

 means they do not sympathize in the general slumber, but remain 

 in a state fit to be called into action by the particular trains of 

 ideas." This opinion is difficult to understand ; we cannot conceive 

 of organs whose nervous or exciting influence is derived from cen- 

 tral sources, such as the brain, remaining, during sleep, in a state 

 to be acted upon, unless that nervous centre from which they de- 

 rive their excitation were, in itself, morbidly or unduly excited. 

 The opinion of the Germ?n physiologist, Hennings, adopted by Dr. 

 Mason Good, appears far more rational and satisfactory, and ex- 

 plains, as far as the sensorium is concerned, the proximate causes of 

 sleep-talking. " As the stimulant force of our ideas, in dreaming, 

 is often sufficient to rouse the external senses generally, and to 



VOL. IV. NO. XVI. R 



