848 ANNUAL REGISTER, 1809. 



we gradually expose the animal to 

 a more violent cold, and it becomes 

 frozen, death ensues. 



Warmth is the most natural 

 cause of the animal's waking; 

 thereareothercauses, however, and 

 cold is one of them. When the 

 animalawakesfromanygiven cause, 

 respiration and circulation recom- 

 mence with the usual degree of heat. 

 The profoundness of the sleep is 

 different, according to the species. 

 Some animals awake several times 

 in winter; the bear and the badger 

 are subject to a slight sleep only ; 

 the dormouse allows itself to be 

 dissected without exhibiting any 

 signs of pain. 



They evacuate their bowels be- 

 fore going to sleep ; but they eat 

 during the short times in which they 

 are awake ; they transpire but very 

 little. The above are such facts as 

 have been clearly ascertained. 



With respect to the predisposing 

 causes, i. e. why some animals arc 

 subject to sleep in winter, and others 

 not, and with respect to the pre- 

 serving causes, i. e. what renders 

 them susceptible of reviving, not- 

 withstanding the suspension of 

 functions which seem most neces- 

 sary to life, — nothing yet has been 

 advanced which offers a satisfacto- 

 ry solution of these questions. 



On the Generation, and other ob- 

 scure Jacts in the Natural Historij 

 of the commo7i Eel. By Mr. R. 

 Carr, of Manchester. [^From 

 the Philosophical Magazine for 

 October, 1809.] 



In all inland waters eels abound 



without number in summer, but 

 disa|)pear in winter. This disap- 

 pearance has been variously ac- 

 counted for, and it has been very 

 generally imagined that a large 

 proportion hibernate by bedding 

 themselves in mud; a notion 

 which, I believe, is quite as vi- 

 sionary as the hibernation of swal- 

 lows under water. Were eels ever 

 in the habit of penetrating into 

 mud, they would naturally enough 

 shelter themselves therein when ex- 

 posed to imminent danger, and no 

 other mode of escape presented it- 

 self; but I have seen very many 

 instances of muddy pools, pur- 

 posely and speedily drained off, 

 where multitudes of eels crawled 

 over the light surface of the mud 

 in all directions to escape, and 

 without ever attempting to conceal 

 themselves by penetrating into it. 

 The full and clear eye of the eel 

 also furnishes evidence that nature 

 never intended the animal to be 

 buried under mud. 



The disappearance of eels in 

 rivers and brooks may be well ac- 

 counted for by their emigration to 

 the sea. This emigration is called 

 their running. It commences in 

 autumn, when immense quantities 

 pass down the streams. Great 

 numbers take the advantage of de- 

 scending with floods, but a large 

 proportion pass downwards in the 

 night, and only in the darkest and 

 most tempestuous nights. Moon- 

 shine wholly suspends their pro- 

 gress; and even a temporary gleam 

 of light, when the nigiit is otherwise 

 favourable, immediately interrupts 

 their journey. This proves that 

 their emigration is not a casual but 

 a premeditated system in their ex- 

 istence ; and it also displays their 



instinctive 



