114 htstinct. 



upon animals as winter approaches, to be thrown 

 off again, without volition, when the warmth of 

 spring makes it no longer needful, but a burden ? 

 Even among plants, we find such change of action 

 according to surrounding conditions, that nothing 

 would save them from being charged with acting 

 by contrivance and forethought, except that they 

 are plants. If a Woodbine {A mpelopsis qui7iquefolid) 

 can find a support on which it can wind its tendrils, 

 it will do so, like the Grape-vine and many other 

 climbing plants ; but if it can find no such support, 

 it will fasten the ends of its tendrils against the 

 smooth walls by broad disks and thus hold itself in 

 place. This beautiful vine was evidently made to 

 climb walls ; and within certain limits, its method 

 of growth changes to meet the circumstances of the 

 case. A bean, which must climb, hunts for a pole 

 by causing the terminal bud to describe larger cir- 

 cles as the vine lengthens. It will find the pole on 

 one side of the hill as well as on the other within 

 certain limits, — that is, if the pole is near enough 

 for the vine to reach it before its weight brings it 

 to the ground. It will, even then, often make a sec- 

 ond attempt from its new centre of support. The 

 eyes or buds of the potato may be pointed towards 

 the centre of the earth, but when the sprouts start 

 they will bend and, avoiding all obstacles that op- 

 pose them within certain limits, will push their way 

 to the light. These and a multitude of other plants 

 not only show adaptation of means to ends in 

 their mode of growth, but the mode of growth va- 

 ries according to the conditions in which the plant 



