X INTRODUCTORY REMARKS. 



discovering any thing new in their economy. So 

 far is this from being the case, that we doubt not if 

 any one were to lay himself out patiently to watch, 

 and carefully to observe, the habits of the Mice that 

 infest our cupboards, or the Sparrows that throng 

 our housetops, he would find highly interesting and 

 unknown facts resulting from his minute observation, 

 which would abundantly repay his labours. 



Naturalists may be divided into two classes, accord- 

 ing to the department of study in which they labour. 

 The first are those who, by philosophic induction, 

 comprehensive research, and enlarged generalization, 

 endeavour to discover " the grand and harmonious 

 plan upon which all organic creation is believed to 

 have been formed," to trace, link by link, the com- 

 plex folds of that mighty chain which runs through 

 all orders of being. The other class consists of that 

 far more numerous body, who choose the humbler 

 sphere of field observation, a task to which no capa- 

 city is incompetent, and in the prosecution of which 

 there is a peculiar freshness which never satiates. 

 But it is obvious that, to give definiteness and pre- 

 cision even to field researches, some arrangement is 

 necessary ; and the labours of many honoured names in 

 science have been devoted to the formation of systems 

 in which any newly discovered form should, more or 

 less obviously, take its place. The points of differ- 

 ence and resemblance in structure or habits which 

 have been selected as the foundation of systems, 

 are very various: we shall mention a few of the 

 classifications adopted from earliest times. 



