394 ZOOLOGICAL PHILOSOPHY 



We likewise recall any person or object that we have previously 

 seen and noticed ; and in the same way we recall complex ideas that 

 we have acquired. 



Our ideas, then, are specific images or outhnes impressed on some 

 part of our organ of inteUigence, and we only become conscious of these 

 ideas when our nervous fluid is set in motion and transmits to our 

 inner feehng that modification of its movement which it acquired while 

 passing over these outhnes. So true is this, that if during sleep our 

 stomach is disordered or we suffer from some internal irritation, 

 our nervous fluid acquires an agitation which is propagated into our 

 brain. It is easy to conceive how this fluid, when its movements are 

 no longer controlled by our inner feehng, follows no order in passing 

 over the outlines of the various ideas impressed upon it, but brings 

 them into consciousness in the greatest confusion, usually distorting 

 them by strange associations and unbalanced judgments. 



During perfect sleep, the inner feehng undergoes no emotion, and 

 for practical purposes ceases to exist ; consequently it no longer 

 controls the movements of the available portion of the nervous fluid. 

 Thus a sleeping individual is as though he did not exist. He no longer 

 possesses feehng, although the faculty of it is intact ; he no longer 

 thinks, although he still has the power to do so ; the available portion 

 of his nervous fluid is in a state of rest, and since the factor which 

 produces actions (the inner feehng) is no longer active, the individual 

 also can do nothing. 



But if sleep is imperfect, owing to some internal irritation which 

 stimulates an agitation of the free part of the nervous fluid, the move- 

 ments of the latter are not controlled by the inner feehng ; they there- 

 fore occasion disordered ideas and strange and motley thoughts, owing 

 to the haphazard association of ideas that have no relation to one 

 another. Thus are formed the various dreams which we have, when 

 our sleep is not perfect. 



These dreams, or the disordered ideas and thoughts which constitute 

 them, are nothing but acts of memory occurring at random and in 

 confusion ; they are irregular movements of the nervous fluid in the 

 brain, whereby consciousness is filled with disconnected ideas, since 

 the inner feehng no longer exerts its functions during sleep nor guides 

 the movements of the nervous fluid. 



This is why we have dreams when digestion is very difficult, or when 

 we have been much agitated by some great interest or by objects 

 which have stirred us. These produce during sleep a great agitation 

 of our spirits, that is, of our nervous fluid. 



Now these disordered acts are always wrought upon ideas that have 

 been acquired and impressed on the organ of intelligence : an individual 



