414 MAURY ON SLEEP AND DREAMS. 



example of this connexion. Images of objects which 

 have no reality, voices equally imaginary, haunt the 

 brain of the madman as they do that of the dreamer 

 less urgently, indeed, in the latter case, and with power- 

 lessness as to any consequent action, yet still marking a 

 state of the sensorium common to both conditions. 



We might dwell further on this subject, and its 

 curious relations to the phenomena of ecstacy, hysteria, 

 the delirium of fever and drunkenness. But even if 

 not admonished by want of space, we should be taxing 

 the patience of our readers too severely by detaining 

 them longer in this region of shadows, where realities 

 and mockeries are so strangely intermingled, and 

 where mental and bodily states mutually excite, 

 control, or partially annul one another, leaving a long 

 page of problems to be solved, if such solution be 

 ever possible. 



The only topic now remaining to us is that of the 

 physical causes proximately concerned in producing 

 sleep and dreams. Here, again, notwithstanding re- 

 searches recently directed to this part of physiology, 

 and valuable works describing them, we are still forced 

 upon the admission of diversity of opinion and imper- 

 fect knowledge. These researches have chiefly regarded 

 the influence of the circulation upon the functions of 

 the brain, and upon sleep, as one of the most important 

 of them. This varying influence is recognised in every 

 part of the body, and at every minute of life ; but the 

 cerebral circulation has specialities distinguishing it 

 from that of any other organ. The confinement of the 

 brain within the close cavity of the cranium, and the 



