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THE AMERICAN NATURALIST 



[Vol. L 



discussions on sleep that appeared in the British Medical 

 Journal in 1913 and the comprehensive treatise by 

 Pieron 33 (1913) on the physiological problem of sleep, 

 clearly indicate how little has been accomplished in this 

 direction. Buff on 4 (1749), on the other hand, thought 

 that ordinary sleep and hibernation were something en- 

 tirely different. Monti 34 (1905) even now believes that 

 these two forms of sleep have entirely different physio- 

 logical meanings and that hibernation in its phylogenetic 

 study should be compared with the dormancy of lower 

 forms, as well as with ordinary sleep. 



In reply to the question asked by the French Academy 

 of Science over a hundred years ago as to the cause of 

 this lethargy and why it pertains to certain animals, 

 Saissy 35 (1808) stated that the cause fundamentally is to 

 be found in certain anatomical peculiarities such as the 

 enlarged character of the heart, central blood vessels, 

 thorax, abdomen and cutaneous nerves, and the smallness 

 of the peripheral vessels and lungs. To these he also 

 added as important features the liquid quality of the 

 blood and the sweetness of the bile. The diversion of the 

 blood from the surface towards the center of the body, as 

 a result of the external cold, dilates the heart and blood 

 vessels of the thorax, and this interferes with respiration, 

 thus decreasing heat production. As a consequence the 

 animal becomes cold and numb. Prunelle 36 (1811), Bar- 

 kow 15 (1846), Serbelloni 8 (1866) and Blandet' 25 (1864) 

 similarly believed in the importance of such— largely 

 imaginary— morphological features. 



Many investigators have associated hibernation with 

 the nervous system. Claude Bernard 37 (1855-76) thought 

 that the cold acts on an unusually well developed periph- 

 eral nervous system, and by slowing respiration cools the 

 body. This is a loss of stimulus to the heart and muscles 

 and torpor results. Reeve 16 (1809) stated that cold acts 

 on a special organization of the nervous system, which 

 causes diminished respiration, etc.; while Quincke 38 

 (1882) interprets the facts he and others have observed, 



