21 S On mjiscular Moficm, 



gitudinal extension of the cavity of the thorax js cntiTtly 

 obstructed. ITius a confined circulation of 4he* blood is 

 carried on tlirongh the heart, probably adapted to the last 

 weak actions of life, and to it? gradual recomirsencement. 



This diminished respiration is the first step into the state 

 of torpidity ; a deep sleep accompanies it j respiration llieu 

 ceases altogether; the animal tcroperatine is totally de- 

 fctroyod; coldness and insensibility take place; and finally, 

 the heart concludes ii* jnctions, and the muscles cease to 

 he irritable. It is worthy of remark, that a confined air, 

 and a confined respiration, ever precede these phsenomena ; 

 the animal retires fronni the open atinosphcre, his moislh 

 and nostrils are brought into contact with his chest, and 

 enveloped in fur; the lianbs becoiiie rigid, but the blood 

 never coagulates during the dormant state. On being 

 roused, the animal yawns, the respirations are fluttering, 

 the heart acts slowly and irregularly, he begins to stretch 

 out his limbs, and proceeds in quest of food. During this 

 dormancy, the animal may be frozen \\ ithoiit the destruc- 

 tion of the n)nsciilar irritability ; and this always happens 

 to the garden snail*, and to the ciirysalides of many insects 

 during the winter of this cliniate. 



The loss of motion and sensation from the influence of 

 low temperature accompany each other, and the capillaries 

 of the vascular system appear to become contracted by the 

 loss of animal heat, as in the examples of numbness from 

 cold. Whether the cessation of.muscular action be oxving 

 to the impeded influence of the nerves, or to the lowered 

 temperature of the muscles themselves, is doubtful ; but the 

 known influence of cold upon the sensorial system, rather 

 favours the supposition that a certain temperature is neces- 

 sary for the transmission of nervous influence as well as 

 sensation. 



The hybernating animals require a longer time in drown- 

 ing than others. A full grown hedge-bog was submersed 

 in water at 49", and firmly retained there : air bubbles be- 

 gan instantly to ascend, and continued during four minutes: 

 the animal was not yet anxious for its liberty. After sevea 

 minutes it began to look about, attempting to escape ; at 

 ten minutes it rolled itself up, only protruding the snout, 

 vhich was hsslily retracted on being touched with the 

 finger, and even the .npproach of the finger caused it to re- 

 tract. After fifteen muiute^ complete submersion, the ani- 

 jijal st^U remained idled up, and withdrew its nose on being 



• lielir jtemoTalii. 



touched. 



