98 Natural Theology. 



perfection with which instinct supplements function, 

 and thus completes the adaptation of each species 

 to the world. 



In the bird, instinct goes further still ; and in every 

 case there finally comes to be a conscious relation 

 of the parent to the young. It hardly seems possi- 

 ble that all the acts that relate to the young are 

 performed with a consciousness of the coming pa- 

 rental relation. Undoubtedly the migration of the 

 bird is as much a matter of blind impulse as the mi- 

 gration of the fish. We judge so because we see 

 the bird following such a uniform line of action in 

 other respects. In certain things, birds of the same 

 species act under the guidance of instinct with as 

 great uniformity as the same species of trees in the 

 arrangement of their leaves, or the pattern of their 

 flower. So that while the act is truly voluntary, it 

 is as certain to take place under similar conditions 

 as any organic change in a plant, and the act is per- 

 formed by a wisdom and skill given, and not acquir- 

 ed. The bird that has never seen a nest will build 

 one as all its kind have done before, selecting the 

 same class of materials and combining them in the 

 same manner. If there is any conscious relation to 

 the young that should lead to the preparation of the 

 nest, how can we account for that impulse that thus, 

 without instruction, induces every bird of the same 

 species to build of the same materials, to select 

 similar situations, and to weave those materials in 

 the same manner? A hundred different species of 

 birds of the same size, and, so far $s we could judge 



