LEAF AND TENDRIL 



a true mechanic and widens her foundation gradu- 

 ally as she comes upward, till she has a shelf of mud 

 wide enough to stand it on. It is aU fit and well 

 considered. We may think that the bird reasoned, 

 and fail to see how inevitable all such things are 

 in organic as well as in inorganic nature. The trees 

 buttress themselves at their base by a circle of high 

 curving roots, and how their branches are braced 

 and reinforced where they leave the trunk ! 



The beaver building its dam seems like a rea- 

 sonable being, and L. H. Morgan, who studied 

 this animal in its native haunts in Wisconsin, and 

 ' wrote the best monograph upon the subject that has 

 ever appeared, thinks that it does reason; but 

 one incident alone which he mentions shows by 

 what unreasoning instinct the animal is guided. 

 He saw where the beavers had built a dam by the 

 trunk of a tree that had fallen across a stream, but 

 instead of placing their sticks and brush against 

 the upper side of the tree, so as to avail themselves 

 of it in resisting the force of the current, they had 

 placed them below it, so that the tree helped them 

 not at all. Poor things! they encountered a new 

 problem. They could build a dam, but they could 

 not take advantage of the aid which the wind had 

 offered them. Probably, had they felled the tree 

 themselves, their instinct would not have blundered 

 so in dealing with it. 

 As animals get along very well without hands 

 194 



