REVEtlY, AND TRA^!CE. * 273 



expianation of this state of being ; I only advert to the fact : tliough if 

 we had time I do not think it would be impossible to suggest an explana- 

 tion 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 involuntary organs. For these, in the first place, are far less subject 

 to exhaustion than the organs either of external or internal sense ; their ac- 

 tions in a state of health being always more equable and uniform : and hence, 

 secondly, from an independence most wisely ordained, and productive of 

 the utmost benefit to the genei*al system, they never catenate with any 

 other actions, except in cases of extremity. Upon an application, how- 

 ever, of very strong stimuli, whether external, as those of severe pain, or 

 labour, or internal, as those of disease or excessive grief, the vital or 

 involuntary organs themselves are fatigued and exhausted ; and when the 

 exhaustion is complete, they also, like the organs of external sense, sleep 

 or become torpid : in other words death ensues, the living principle 

 ceases, and the spirit separates from the body. The resemblance, there- 

 fore, between death and sleep is not less correct upon the principles of 

 physiology, than it is beautiful among the images of poetry. Sleep is 

 the DEATH or torpitude of the voluntary organs, while the involuntary 

 continue their accustomed actions. Death is the sleep or torpitude of 

 the whole. 



Every organ of the animal frame recovers from its fatigue or torpor by 

 rest, provided the principle of life continues. Hence the organs of exter- 

 nal sense, in a definite period of time, and a period generally propor- 

 tioned to the degree of their exhaustion, re-acquire their accustomed ♦ 

 vigour, are alwe to the influence of their appropriate stimuli ; and the 

 smallest excitement applied to any one of them, throws the whole once 

 more into action, in consequence of their habit of acting associately and 

 by common consent. In other words, the man awakes from sleep ; he 

 rouses himself from the temporary death of the organs of external sense. 

 Were it possible for the principle of life to continue during a total rest or 

 torpitude of the vital or involuntary organs, as it does during that of the 

 voluntary, there can be no doubt that these also would, in time^ recover 

 from their exhaustion ; and that the man would, in like manner, awake 

 from the total torpitude, the sleep or death of the entire frame ; but this 

 in man, excepting under very particular circumstances, and circumstances 

 I shall advert to presently, is impossible. The rule of nature is, that as 

 soon as the vital or involuntary functions are discontinued, the principle 

 of life ceases ; the soul deserts the body ; the laws of chemistry, hitherto 

 held in subjection by a superior control, assert their authority ; and the 

 whole visible system falls a prey to corruption and ruin. 



When the organs of external sense have recruited themselves by repose, I 

 have already observed that the stimulus that rouses the one, rouses at the 

 same time the rest, from a habit of association. From the same habit, 

 the torpitude produced by exhaustion in any single organ is propagated 

 through every other, and the sleep becomes common to the whole ; 

 although it is also unquestionable that the whole are fatigued, or partially 

 exhausted, in consequence of the general stock of sensorial power having 

 been borrowed, in a considerable degree, from the rest, and expanded at 

 a single outlet. 



The sensitive fibres of the organs of external sense are equally af- 

 fected, ami of course become equally exhausted, whetbe^r a stimulus bo 



3^ 



