HYBERNATION. 145 



functions of animal life are never totally suspended during 

 winter. 



There appears to be also some continuance of vital ac- 

 tivity amongst plants, as for example, evergreens. From 

 the very nature of things these plants must change their 

 leaves j but they do it in a manner less rapid and visible, 

 one leaf replacing the other in such a way that the tree is 

 never totally defoliated. In the spring of the year there 

 is a partial leaf-fall from the branches of evergreens. 

 These plants therefore retain their capillaries, which are 

 more or less in action through the winter months. 



A low degree of warmth will, even in the depth of 

 winter, start the sap of plants. Thus, if incisions be 

 made into the stem and branches of a young maple in 

 winter, if the weather should become mild, the sap wiHr 

 be seen to trickle from the wound. So also coniferous 

 plants, which abound in resin, maintain their temperature 

 above the freezing-point in the severest weather. Their 

 fluids are never congealed, owing to their viscidity, and 

 they can therefore resist the cold when it destroys all the 

 vegetable life around them. 



Vegetable and animal life is therefore more or less in 

 a state of activity during the winter months, although as 

 a general thing, winter is a state of repose to all the lower 

 forms of organized nature, the nutritive fluid slowly accu- 

 mulating in their tissues. 



But the vernal sun once more pours forth on the cold, 

 damp earth, his warm, life-giving radiance ; the earth and 

 atmosphere are by the force of vital attraction again woven 

 into green leaves and beautiful flowers, and the animal crea- 

 tion issue forth from their hiding-places to partake of the 

 rich feast. This rapid development of vegetable and animal 

 life, together with all its varied and deeply instructive 

 13 



