f 86 THE POPULAR SCIENCE MONTHLY. 



around us, and to shield us against the inclemency of the seasons. 

 The animal, in this happier than man, has no need of dress Nature 

 supplying it with plumage or with fur but yet is required to build 

 for itself the dwelling-place where it is to find shelter. May we sup- 

 pose that here, too, Nature provides for every thing, and that blind 

 instinct guides the bee in the construction of her cell, and the bird in 

 the building of its nest ? Such, indeed, is the opinion of most natu- 

 ralists, and their chief argument is drawn from the fact that birds al- 

 ways follow the same plan in building their nests, while man is ever 

 modifying and improving bit by bit his methods of construction. But, 

 now, is this argument based on unquestionable facts, or is the conclu- 

 sion legitimate ? An English naturalist, Mr. Alfred Russel Wallace, 

 undertakes to prove the contrary, in his work on Natural Selection. 

 According to him, the bird does not build its nest by instinct ; and 

 the mental faculties it exhibits in this operation are of an identical 

 order with those exhibited by man when he builds a house. In short, 

 it is claimed that these faculties are simply imitativeness, and a sort 

 of rudimentary ratiocination, which can take account of external sur- 

 roundings, whatsoever they may be. Hence it is that birds do change 

 and improve their processes of construction, under the influence of 

 such causes as determine progress in man ; and, in turn, man is at a 

 stand-still when he receives no impetus from without. 



What is instinct ? It is " the faculty of performing complex acts, 

 absolutely without instruction or previously-acquired knowledge." 

 Instinct, then, would enable animals to perform spontaneously acts 

 which, in the case of man, presuppose ratiocination, a logical train of 

 thought. But, when we test the observed facts which are usually put 

 forward to prove the power of instinct, it is found that they are sel- 

 dom conclusive. It was on such grounds that the song of birds was 

 taken to be innate, albeit a very ready experiment would have shown 

 that it comes from the education they receive. During the last century 

 Barrington brought up some linnets, taken from the nest, in company 

 with larks of sundry varieties, and found that every one of his linnets 

 adopted completely the song of the master set over him, so that now 

 these linnets larks by naturalization formed a company apart when 

 placed among birds of their own species. Even the nightingale, whose 

 native song is so sweet, exhibits, under domestication, a considerable 

 readiness to imitate other singing-birds. The song of the bird is, there- 

 fore, determined by its education, and the same thing must be true as 

 to nest-building. A bird brought up in a cage does not construct the 

 nest peculiar to its species. In vain will you supply all the necessary 

 materials : the bird will employ them without skill, and will oftentimes 

 even renounce all purpose of building any thing like a nest. Does not 

 this well-known fact prove that, instead of being guided by instinct, 

 the bird learns how to construct its nest, just as man learns how to 

 build a house ? This observation might be made complete, if we were 



