THE PHYSIOLOGY OF SLEEP. 



4*3 



it made no attempt at self-defence, neither resisting nor escaping. In 

 fine, it lost every trace of intelligence, for it neither willed, remem- 

 bered, felt, nor judged : yet it swallowed food when the food was put 

 into its mouth, and fattened. In these cases, as in that of the injured 

 man, the involuntary systems sustained the animal life. It is the same 



in sleep. 



Fig. 1. 



Organic Nervous System which controls the Heart and the Organic Processes, and never sleeps. 



When we look at these phenomena, as anatomists, we find a reason 

 for them in structure and character of parts. The involuntary mus- 

 cles have a special anatomical structure ; and the nervous organism 

 that keeps the involuntary muscles in action is a distinct organism. 

 There are, briefly, two nervous systems : one locked up in the bony 

 cavity of the skull and in the bony canal of the spine, with nerves 

 issuing therefrom to the muscles ; and another lying within the cavi- 

 ties of the body, with nerves issuing from it to supply all the involun- 



