VI PREFACE. 



furnish a systematic catalogue of animals, with its exposition lim- 

 ited to the frigid details of anatomical structure. This would 

 restrict it to dead rather than to living forms. Each animal is 

 endowed with a living, and, also, with a thinking principle, the 

 manifestations of each of which are not less important and in- 

 structive than the mechanism of the material frames in which 

 they reside. In a comparative sense the former are intrinsically 

 of higher concernment. 



A monograph upon each of the principal animals seems, there- 

 fore, to be desirable, if not absolutely necessary, to fill out, in 

 some measure, this great programme ; and to complete the super- 

 structure of a science, the foundations of which have been so 

 admirably established. These should contain a minute exposi- 

 tion of their artificial works, where such are constructed ; of their 

 habits, their mode of life, and their mutual relations. When the 

 facts bearing upon these several subjects have been collected and 

 systematized, the necessary materials will be furnished for the 

 proper elucidation of the long neglected subject of Animal Psy- 

 chology. 



This volume upon "The American Beaver and his Works," 

 although it falls much below the dignity and completeness of a 

 monograph, is offered as an experiment in this special undertaking 

 of collecting and systematizing our knowledge of the habits and 

 mode of life of the inferior animals. Whether the zoologist will 

 turn aside from the more intricate and fascinating subjects of his 

 science to consider the personal acts and artificial erections of 

 this humble, but most industrious mute; and whether the general 

 reader will find either pleasure or profit in studying the manifest- 

 ations of intelligence by a single animal, when spread out with 

 so much detail, I cannot pretend to form an opinion. A treatise 

 overdone is as distasteful to the reader as one imperfectly exe- 

 cuted ; and since this is liable to both objections, it is submitted, 

 not without misgivings, to the public judgment. 



As books of this description are more or less accidental pro- 

 ductions, it is sometimes proper to state how they came to be 

 ■WTitten. Notwithstanding some reluctance to enter upon per- 

 sonal details, there is, in the present case, an urgent necessity 

 for a brief explanation to bespeak the confidence of the reader 

 in the results of this investigation. It furnishes an apology for 

 introducino,' the following statement. 



