232 THE POPULAR SCIENCE MONTHLY. 



together with its conscious control over the nerves of the volun- 

 tary muscular system. Reasoning power is annulled, but invol- 

 untary and instinctive muscular motions, and those arising from 

 habit, still continue. Memory is certainly not annulled, or we 

 should never dream of the past, of which we do dream largely. 



The consciousness of Duration that deepest of all mysteries 

 is not absent in sleep, but also passes wholly out of the control of 

 the reason and the memory, and loses all relation to the condi- 

 tions of waking experience, being often exaggerated or exalted 

 far beyond these. Unconsciousness of duration occurs during the 

 waking dream state, being here suspended at times, so that lapses 

 of time remain unnoticed. Those subject to intense mental occu- 

 pation, or to reverie, which is a species of waking dream, will 

 attest this. Strong emotions also influence our consciousness and 

 perception of duration. 



It may be objected that the above description of sleep does not 

 cover a species that general readers have been taught to consider 

 tJT-pical what is called "dreamless sleep." This, however, is 

 probably a literary fiction. Even the "dreamless sleep of in- 

 fancy " is not always realized, for healthy infants often present 

 indications of dreaming. Sleep so deep as to be dreamless is 

 probably not of the most natural kind, but rather the result of 

 nervous, mental, or muscular exhaustion, or of drugs, being thus 

 a more or less morbid letharg5\ 



No one would claim that natural dreams are symptomatic of 

 morbid conditions, though of course certain kinds of dreams as 

 those from opium, of delirium tremens, dyspeptic nightmares, 

 etc. are such. These, moreover, are often a kind of waking 

 dream, in which the body remains more or less awake while the 

 mind is lethargic or deliriously excited. 



It thus appears that sleep is far from being the simple affair 

 it was held to be in the last century. On the contrary, it is a 

 highly complex phenomenon, involving all the functions mental, 

 moral, and physical, and doubtless also physiological of that 

 most complex of all organisms, man. Hence, it must be worthy 

 of far closer scientific study than it has yet received. 



As to the physiological and chemical phenomena that accom- 

 pany sleep in the animal economy : Of this the most essential 

 branch of the investigation it must be stated that its cultivation 

 has been very imperfect and inadequate. Still, enough is known 

 to convince the present generation of chemical thinkers that sleep 

 is by no means a subject for the psychologist alone, but will turn 

 out to be physiological and chemical that is, accompanied, and 

 even almost altogether ruled, by chemical agencies and transfor- 

 mations. We have here a strong and sound basis for the hope of 

 arriving at a control of natural sleep itself and at modes of influ- 



