132 Rev. P. Keith 07i the Conditions of Life. 



dressed ; and yet the temperature of the bod}' never rose be- 

 yond 101° of Fahrenheit*. Tlius there is in plants and in 

 animals something that resists and controls the influence of 

 chemical ajjents, and that something js the attribute of life. 

 The dead animal substance, the beaf-steak, was broiled, but 

 the living animal substance remained unaffected. 



Connected with temperature we have the very singular pluc- 

 nomenon of the hybernation of plants and animals, that is, 

 of some peculiar species of them : for all plants and animals 

 do not Jiybernate. The state of hybernation is a state of tor- 

 pidity, induced by a low temperature, and lasting till the colds 

 of winter have gone. The living functions are suspended. 

 In plants there is no absorption, no nutrition, no flux of juices. 

 In animals, there is no respiration, no assumption of aliment, 

 nor circulation of fluids; or, if this last process is at all carried 

 on, it is in the most languid manner. Yet life is not extin- 

 guished ; it is not even injured," but rather it is preserved 

 from accidents that might be fatal to it ; and when the return 

 of spring restores again the due temperature, the individual 

 resumes its living functions, and its hybernation ceases. 



Among plants, the bulbous-rooted are said to hybernate, 

 and the bulb is regarded as being the winter-quarters of the 

 future plant. They do not however hjbernate in the strictest 

 sense of the term ; for if you leave them in the soil for the 

 winter, and inspect them now and then, you will find traces 

 of the growth and development of the infant plant, even in 

 the season of hybernation. — But the hybernation of animals is 

 the most complete. In them the living functions are really 

 and truly suspended, and no traces exhibited of the growth 

 of parts. The snake, the dormouse, the swallow +, the bat, 

 are examples of hybernating animals. They roll themselves 

 up into the smallest compass possible, and, as it may best suit 

 the species, take up their winter-quarters in the earth, or in 

 clefts of rocks, or in holes of walls looking to the south. If 

 you detect them in their hiding-place, you may handle them 

 or pinch them or roll them about; and they shall know 

 nothing of it till they are exposed to the influence of a gradual 

 warmth. Their torpor is said to be the most profound at the 

 temperature of from 5° to 7° above zero. If they are sud- 



* Phil. Trans, (abridged by Hutton), vol. xiii. p. 695. 



I Much has been written about the annual disappearance of swallows j 

 some maintaining that they hybernate; others that they merely emigrate. 

 It is certain that such stragglers as have not joined in the general flight 

 do actually hybernate. This I can affirm with confidence, from the fact of 

 my having once found, in the midst of winter, a solitary swallow, in a 

 torpid state hybernating under the thatch that covered the ridge rafter of 

 the roof of a carpenter's shop. It revived upon being exposed to the 

 wnvmth of a fire ; but the weather being still too cold, it soon died. 



denlv 



