Xll INTRODUCTION. 



facts and phenomena, would be too unconnected 

 in their relations to serve any practical or useful 

 purpose. When the animal system is patiently 

 investigated, by means of well-directed experi- 

 ments and deliberate observations, many mys- 

 teries are cleared up, and many intricacies are 

 solved. When the laws of the constitution are 

 thus examined, the results are similar to those 

 that DUGALD STEWAIIT has described in respect 

 to the operations of the mind, when studied with 

 care : " Upon a slight attention to the oper- 

 ations of our own minds, they appear to be so 

 complicated, and so infinitely diversified, that it 

 seems to be impossible to reduce them to any 

 general laws. In consequence, however, of a 

 more accurate examination, the prospect clears 

 up ; and the phenomena, which appeared at first 

 to be too various for our comprehension, are 

 found to be the result of a comparatively small 

 number of simple and uncompounded faculties, 

 or of simple uncompounded principles." 



We must guard against being too indulgent 

 either to the experimentalist or theorist. The re- 

 sults obtained by the former require a more criti- 

 cal investigation than they generally receive, 



