Architecture in the Animal Kingdom. 123 



their domes accordingly; and, just as beavers use 

 their architectural skill not only in building nests but 

 also in constructing dams and canals, so ants use theirs 

 for far more various purposes. Those who concur 

 with Romanes in maintaining that *'the adaptations 

 of pure instinct have reference only to conditions that 

 are unchanging"^, and that meeting of continual vari- 

 ation of conditions cannot be accounted for but by 

 intelligence, must, indeed, attribute to beavers a con- 

 siderable degree of individual intelligence, but no less 

 to ants. However, this conception of instinct and 

 intelligence is untenable. Even Romanes is loath to 

 ascribe to beavers such high psychic faculties, yet 

 with his false notion of intelligence this conclusion is 

 unavoidable. If beavers in modifying their buildings 

 are guided by their own reasoning, they must be like- 

 wise credited with an intelligent knowledge of the 

 principles of their architecture ; for the former without 

 the' latter is impossible ; thus, we have, instead of 

 their building instinct, the highest order of human, 

 architectural intelligence ! This is evidently untenable. 

 Those, however, who explain the architectural instinct 

 of beavers from the hereditary disposition of their 

 sensitive cognition and appetite, are able to explain 

 from the same principle any given modification of their 

 architecture, without resorting to "animal intelli- 

 gence." 



5. Other Purposes for Which Ants Employ Their 

 Architecture. 



Some ants havmg populous colonies often establish 

 temporary stations at the foot of trees and bushes. 



L. c, p. 377. 



