MAURY OX SLEEP AND DREAMS. 381 



The first step we have to make here is one essential 

 to any successful prosecution of the inquiry. It is 

 based on the clear recognition of the fact, that sleep, 

 thus associated, is not one state merely, but a multiplicity 

 and continuous succession of states ; varying at every 

 moment in kind or degree ; graduating from the first 

 yawn of drowsiness to the most profound sleep, and 

 undergoing similar changes in the transition from this 

 to the state of perfect wakefulness. Even thus simply 

 stated, it will be seen how completely this fact governs 

 and gives guidance to the whole enquiry, rendering its 

 conditions, indeed, more complex, but affording a clue 

 to many collateral phenomena otherwise wholly inex- 

 plicable. Sir H. Holland, who has two chapters on 

 Sleep and Dreams in his volume of ' Mental Physiology,' 

 strongly advocates this mode of treating the subject. 

 We avail ourselves of a short passage from one of these 

 chapters in illustration of our meaning : 



' Sleep, then, in the most general and. correct sense of the 

 term, must be regarded not as one single state, but a succes- 

 sion of states in constant variation this variation consisting, 

 not only in the different degrees in which the same sense or 

 faculty is submitted to it, but also in the different propor- 

 tions in which these several powers are under its influence at 

 the same time. We thus associate together under a common 

 principle all the phenomena, however remote and anomalous 

 they may seem from the bodily acts of the somnambulist ; 

 the vivid but inconsequent trains of thought excited by 

 external impression; the occasional acute exercise of the 

 intellect ; and the energy of emotion to that profound 

 sleep in which no impressions are received from the senses, 

 no volition is exercised, and no consciousness or memory is 



