468 Midler's Archie fur Anatomic, Physiologie, §-c. 



Hybernation of Animals. By Dr A. A. Berthold. Although 

 many reasons have been assigned to account for the sleep of several 

 of the Mammalia during winter, Otto seems to be the first who has 

 attributed it to a peculiar organization of the vessels of the brain, 

 and not merely to a decrease in the temperature of the air. [The 

 result of his latest researches tends to show, that the carotis cere- 

 bralis in such animals is carried through the aperture of the stapes 

 or stirrup bone.] 



Dr Berthold has kept for some time specimens of Myoxus avel- 

 lanarius, some of which were captured when full grown, and others 

 quite young in the nest. His observations upon them tend to con- 

 firm those of Pallas, Spallanzani, &c, and in some instances to cor- 

 rect the statements of other writers on the subject. The animals 

 fell asleep whether they were kept in the open air or in a warm 

 room. Saissy states, that Myoxus glis did not fall asleep until the 

 temperature was below 44° Fahr. Dr Berthold's specimens of M. 

 avellanarius were kept during the winter in a room, the temperature 

 of which was never below 50°, usually from 59° to 63°, and some- 

 times as high as 68°, and they slept without intermission. Their sleep 

 is more profound in a low than in a high degree of temperature, so 

 that in the former case they may be shaken about for a long time with- 

 out producing any effect, but in the latter, the shaking causes them 

 to roll themselves up still more firmly, by pressing the head upon 

 the breast, but even then they do not awake. Those kept in a warm 

 room remained longer awake than others in a cold one. In October 

 the latter began to sleep continuously, some, however, awoke every 

 day for some time longer and took some food. Towards the middle 

 of December their sleep became deeper and deeper, and from that 

 time till the middle of March they only awoke two or three times 

 at most. The sleep of those which were kept in a room of ordinary 

 warmth was modified by sudden changes of weather, until it reach- 

 ed the most profound state. When snow or frost was coming on 

 they slept more soundly ; as the weather became milder they were 

 more active, and often awoke for several hours, when they took 

 some food, which they digested completely and then relapsed into 

 sleep. Whenever they awoke under any of these circumstances, 

 their character as nocturnal animals remained constant, as it always 

 happened in the evening or during the night. When old ones, and 

 their young which had not passed a winter, were kept together, the 

 former fell asleep first, as the latter, not yet having attained their 

 full growth, required more food, and their sleep was retarded by the 

 calls of hunger. The temperature of the animals during their sleep 



