OF SLEEP. 551 



the apparatus for the reception of external impressions, as well as that 

 for voluntary action, may be failing, it implies nothing as regards the 

 prime mover. The eye may be dim, the ear dull, and touch imperfect, 

 the voice may be feeble, and the limbs trembling, but all this indicates 

 nothing more than that what has been passed through so often before 

 is about to be passed through again. The organs that have done their 

 duty are to be cast away, but the result of their action is to remain. 



It may not, perhaps, fall within the proper compass of a treatise on 

 physiology to speak of that future condition, and yet so deeply The future 

 interesting are these subjects to all men that a single observa- state - 

 tion may in this place be excused. The whole course of life, from its 

 very beginning, has been one of development and concentration. We 

 comprehend this the more perfectly as we extend our views beyond our 

 present state, and examine what we have in succession been, and in what 

 manner our existing condition was reached. It is not credible that that 

 system is to be all at once abandoned, or replaced by a contradictory one. 

 Such is not the style in which the affairs of the organic world are at any 

 time carried on. The slowly emerging consequences of the primitive 

 law ccme forth one after the other in their proper and unvarying sequence, 

 and the law holds on inexorably forever. And since we may say that, 

 throughout those prior states, the idea aimed at is the isolation of a con- 

 scious intelligence, every organ being shaped and every function bent to 

 that end, we are reasonably led to the expectation that in a future state 

 that archetype will be completely reached. It would be strange indeed 

 if a blank oblivion should crown such a work. 



CHAPTER VI. 



OF SLEEP AND DEATH. 



Causes of the Necessity for Sleep. Its Duration and Manner of Approach. Manner of Awak- 

 ing. Cause of Night-sleep. Increased Warmth required. Connection of Sleep and Pood. 



Of Dreams : their Origin and Phenomena. Somnambulism. Nightmare. 



Of Death. Old Age. Internal Causes of Decline. Death by Accident and by Old Age. The 

 Hippocratic Face. Final Insensibility. 



Isx. OF SLEEP. 



ONE third of the life of man is spent in sleep, a condition of modified 

 sensibility, in which the mind performs its functions in an im- 

 perfect way, and voluntary motion is nearly suspended. This 

 state, occupying so large a portion of the short period of time allotted to 

 us, is therefore well deserving of the consideration of the physiologist, 



