Conjectures on the proximate Cause of Sleep. 259 



perpetual sleep ; but the animal organs, never haviyig yet leen 

 exercised, can hardly be said to be in a state of repose *." " The 

 state of torpidity," he continues, " in which many animals pass 

 the winter months, cannot properly le called sleep ; it is not the 

 repose of the animal organs consequent on fatigue produced by 

 their exercise, but is a peculiar condition of the whole frame, 

 affecting the internal as well as the external organs, and caused 

 directly by the action of the cold f." 



These two causes are alike in one particular, the sleep is not 

 repose after fatigue. In the former, the process of assimilation 

 is proceeding in every part of the frame, and in the brain as well 

 as elsewhere — its operation, therefore, cannot be excluded from 

 such participation in the phsenomenon as it may be reasonable 

 to assign it. In the latter case it is well known that the bear, 

 the marmot, and other hybernating animals retire to their win- 

 ter's repose in a state of corpulence and obesity, which they lose 

 before they shake off their slumber in spring. They use little or 

 ■no food in their retreat, yet the absorption of their superfluous 

 flesh and fat may be applied by the assimilating process to the 

 nourishment of the superior organs, including the brahi. If the 

 cold alone reduced them to a state of torpidity, by paralysing 

 this organ, their emaciation would still remain to be accounted 

 for; but the action of the absorbents and the process of assimi- 

 lation remove every difficulty and explain every fact. 



In complete sleep, hunger and thirst are not felt, as remarked 

 by the same writer, " yet great hunger prevents sleep ; and cold, 

 affecting a. part of the body, has the same effect. These causes 

 operated on the unfortunate woman and her family, who lived 

 thirty-four days in a small room overwhelmed by the snow, with 

 the slightest sustenance: they hardly slept the whole time |." 

 It does not clearly appear why the cold should have affected only 

 a part of the body, and it is declared by this writer, " that in- 

 tense cold, affecting the whole lody, exhausts the animal powers 

 and brings on sleep, which is speedily fatal §." The only facts 

 certain in this account are, that they lived for thirty-four days 

 with the slightest sustenance, and hardly slept the whole time. 

 The process of assimilation might therefore have been only in 

 proportion to the nourishment, and the want of sleep seems to 

 be accounted for by the absence of this process. If the cold had 

 affected only a part of the body, and was not intense, it might 

 have kept the thoughts active, and the exercise of the brain might, 

 for a time, have interrupted the process of a:tiimilation, even if 

 there had l)een the usual supplv of nutriment; but if the cold had 

 invaded the entire frame, and was in the highest state of inten- 



• Rcc3'3 Cyc. lb. t Id. X W- § W- 



R 2 sity. 



