243 



ON SLEEP, DREAMING, 



we be spoken to in this state, we return an answer, which intimates, indeed, 

 that we have heard ; but, by its incongruity with the observations made to us, 

 intimates also that the will has, in some degree, lost its control ; — that it has 

 become drowsy, and is affected by the slumber of the organs of external sense. 



If the general exhaustion be not very considerable, as after dinner, or during 

 the digestion of any other meal, the sleep may not extend beyond this first 

 or simple stage of slumber; though it should be observed that, from the 

 power of association, the internal and external senses have a strong tendency, 

 if in health, to concur or catenate in one common state or action. When 

 the one are in full vigour, the other are usually in full vigour also; and when 

 the one become drowsy, the other incline to tlie same drowsiness. But if 

 the general exhaustion be more violent than we are now contemplating, the 

 internal senses will unquestionably concur in the effect, and evince, in some 

 or all of them, an equal degree of sleep. 



The first of the internal senses that becomes thus influenced is the will 

 Itself. It would be easy to show, if we had time, that the will is infinitely 

 more disposed to catenate with the motions of the external senses than any of 

 the other faculties of the mind. It hence gives way first of all, and sleeps 

 along with the exterior organs, while the other faculties of the mind remain 

 awake. We are now arrived at the second stage of sleep ; and it is this which 

 we call and which constitutes dreaming. The will catenates in the sleep 

 of the organs of exterior sense ; but all the interior senses, except the will, 

 are still awake. Hence we have ideas of memory, ideas of consciousness, 

 ideas of imagination, ideas of reasoning: but, destitute of a controlling 

 power, they rush forward with a very considerable degree of irregularity, 

 and would do so with the most unshapeable confusion, but that the power of 

 association still retains some degree of influence, and produces some degree 

 of concert in the midst of the wildest and most extravagant vagaries. And 

 hence that infinite variety that takes place in the character of our dreams; 

 and the greater regularity of some, and the greater irregularity of others. 



But the general fatigue and exhaustion may be still more violent ; and it 

 may also be produced by motions in which the internal senses have princi- 

 pally co-operated : and in such cases, not the will only, but the whole of the 

 internal senses concur in the common torpor or inertness that is produced : 

 and we now advance to a third state, which I shall beg leave to call lethargy : 

 dead, senseless sleep, or a stage of sleep without thought or idea of any 

 kind, but still natural and healthy ; the vital organs, though none but the vital 

 organs, still continuing their action. 



It has been a question often proposed, whether the mind ever does, or ever 

 can, exist without thinking? But it can only have been proposed by persons 

 who have not paid a due attention to a variety of phenomena, which are per- 

 petually occurring, and which must be conclusive as to the fact. The mind 

 of an infant, or rather of a fetus, must anticipate the thoughts or ideas that 

 are afterward introduced within it. In a complete paroxysm of apoplexy, 

 no man has ever been conscious of a single thought or idea ; in sleepy coma 

 or lethargy in fevers, as opposed to restless coma, the same discontinuity of 

 all thought and idea takes place uniformly ; and we meet with it perhaps still 

 more incontrovertibly in all cases of suspended animation from drowning, 

 hanging, or catalepsy. I enter not into an explanation of this state of being; 

 I only advert to the fact : though if we had time I do not think it would be 

 impossible to suggest an explanation that might be satisfactory to every one. 



Thus far we have left the vital or involuntary organs, those over which the 

 will exercises no control, in a state of wakefulness, though none but the in- 

 voluntary organs. For these, in the first place, are far less subject to exr 

 haustion than the organs either of external or internal sense ; their actions in 

 a state of health being always more equable and uniform : and hence, se- 

 condly, from an independence most wisely ordained, and productive of the 

 utmost benefit to the general system, they never catenate with any other 

 actions, except in cases of extremity. Upon an application, however, of very 

 strong stimuli, whether external, as"^those of severe pain or labour, or internal, 



