Homes of Animals, 97 



to other things. In fact those animals which in their 

 structure and mental qualities seem to approach 

 nearest humanity, either build in a very rude man- 

 ner or not at all. In many cases the skill to build 

 seems to be greater as the animal is lower in the 

 scale. Certain it is, that the nest is no test of the 

 capability of the animal in any other direction. It 

 seems to be something which the animal has the 

 impulse to build and the skill to build because it 

 needs it for its own welfare or that of the species, as 

 the silk worm winds the cocoon for a tomb in which 

 to pass to a higher condition of life. 



There are certain things in reference to this ten- 

 dency to build and the skill in doing the work that 

 are not only curious but may have an important 

 bearing upon the theories respecting the origin and 

 development of animals. 



1. We find in some cases the building material 

 wholly or partially secreted from the body of the 

 builder, — as the silk with which the different spe- 

 cies of spiders weave their webs or form their curious 

 nests, and the wax for the Honey-bee's comb. In 

 the case of many other animals the sizing or cement 

 is apparently furnished from the body of the build- 

 er, as in the case of hornets and wasps of various 

 kinds that make paper and the hardest kind of 

 paste-board of woody fiber. The American Swift 

 or Chimney-Swallow, also glues together the sticks 

 to form its nest with a cement from the glands of 

 its throat. 



2. Among animals very nearly allied there is 



5 



