276 STUDIES IN LIFE AND SENSE. 



Sleep is produced by those causes which favour the withdrawal of 

 blood from the brain, or rather by those which lessen the flow and 

 force of the circulation in that organ. As an indication of the need 

 of repair by rest, the bloodless condition of the sleeping brain appears 

 in perfect harmony with the opposite condition of the wakeful 

 state. And thus, also, it may be added, we may construct a reason- 

 able approach to a theory of dreams in the statement that whatever 

 favours an increase of brain-circulation during sleep will develop 

 the dream-instincts, and liberate those dream-children which, 

 Shakespeare notwithstanding, are not to be declared the offspring of 

 " an idle brain." 



That we have a power or faculty of abstracting our thoughts and 

 practically ourselves from the external order of things by which we 

 are surrounded, is, of course, a statement which has but to appeal to 

 our common experience to attest its unquestioned veracity. It is im- 

 portant for our present purpose that we briefly glance at the subject 

 of reverie, inasmuch as we may find a striking analogy between this 

 state as experienced in our wakeful moments, and through the allied 

 state of " automatism," an explanation of the mechanism of dreams. 

 The ordinary sensation, received by an organ of sense from without, 

 is transferred to some part of the brain specially concerned with the 

 registration of such an impression, and is there converted into an 

 idea. This idea in turn may be reflected hither and thither through 

 the body, and appears in our waking life as a defined and purposive 

 action. Suppose, now, that ideas which have been registered in the 

 brain are capable of being despatched or evolved therefrom at will. 

 The production of thoughts thus-wise constitutes memory; and 

 association duly links them together to form " a train of thought." 

 But thought may be unattended by action. A whole train of ideas, 

 or a complicated chain of reasoning, may be thought out in a kind 

 of mental aside, and in that utter want of attention to our sur- 

 roundings which constitutes the essential feature of the "absent- 

 minded man" a phrase applicable only in so far as the term 

 " absent-minded " applies to the immediate circumstances of the 

 individual. Here there is automatic action of the brain pure 

 and simple. The familiar instance of the rapid walk through the 

 crowded streets of a city, whilst the mind is engaged in the pursuit of 

 some recondite subject, is but another instance of the phenomena of 

 abstraction carried into practical effect, and exemplifies an inter- 

 mediate state between sleep and waking allied to somnambulism 

 itself. From our wakeful moments to the reverie in our arm-chair 

 is but a step. From such a reverie to the abstraction of our city 

 walk is only another advance ; and if we suppose the abstraction 

 to deepen whilst the mental activity becomes annihilated, we obtain 

 the dreamless sleep, as, on the other hand, with an increase of the 



