THE PHYSIOLOGY OF SLEEP. 1 



By R. Legendre. 



Sleep is one of the most necessary functions in our lives. It occu- 

 pies a third of our existence. It is therefore not at all strange that it 

 should be a subject of deep study and research by numerous investi- 

 gators; in fact, poets, philosophers, psychologists, physicians, physiol- 

 ogists, and others contemplate the subject and examine it from their 

 several points of view. 



To poets, according to their feeling at the moment, sleep is in turn 

 distasteful or pleasing. Wishing for action, they call it "brother of 

 death," but more frequently, absorbed in reveries and dreams, they 

 banish that thought, for sleep no more resembles death than does a 

 smoothly flowing stream resemble the calm surface of a lake. 



Day is for evil doing, for weariness, and hate. 



Night is the well-beloved, she who brings tranquillity, repose, and 

 dreams; and the poets invoke her, begging her to stay. 



Oh, venerable night, from whose depths profound 

 Through endless space peacefully flow 

 Broad silvery streams from countless worlds, 

 And into man pours calm divine. 



***** 



All life is mute, for 'neath thy spreading wing 

 It drinks of sleep at shade of eve, 

 A milk deep and wondrous, that 

 All lips imbibe in silence at thy dark breast. 



Sully Prudhomme. 



Sleep seems even as a god who, with forehead crowned with poppies 

 and wrapped in dreams, slumbers in the depths of an obscure grotto, 

 isolated by the river of forgetfulness. 



To philosophers, also, sleep is a subject of deep thought. It opens 

 up, indeed, two great problems : First, one may ask what becomes of 

 our consciousness during sleep, and the question is an important one 

 when we agree with Descartes that thinking is proof of our existence. 

 Should we believe that the mind acts continuously in our dreams? 



1 Lecture delivered May 7, 1911, at the National Museum of Natural History, Paris. Translated by 

 permission from Revue Scientiflque, Paris, forty-ninth year, June 17, 1911. 



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