INTRODUCTION. 15 



difficulty of identification greatly sharpens one's know- 

 ledge, induces a habit of paying attention to minutiae, 

 and creates a power of distinguishing between things 

 that differ slightly, which is exceedingly valuable and 

 important. For the eye and mind thus educated to 

 detect resemblances and differences in objects, which to 

 ordinary observation appear widely dissimilar or precisely 

 the same, there will be abundant scope in the practical 

 details of common everyday life, as well as in the higher 

 walks of literature, science, and art. 



The study of these plants has also a tendency to 

 elevate and enlarge our conceptions of nature ; its vast- 

 ness and complexity, its incommunicable grandeur, its 

 all but infinity, opening before us newer and more 

 striking vistas with every descending step we take. The 

 farther we advance, and the wider our sphere of ob- 

 servation extends, wonder follows on wonder, till our 

 faculties become bewildered, and our intellect falls back 

 on itself in utter hopelessness of arriving at the end. 

 Minute as the objects are in themselves, contact with 

 them cannot fail to excite the mind, to call it forth into 

 full and vigorous exercise, to enlist its sympathies, and 

 to expand its faculties. Many eloquent pages have been 

 written to show this elevating influence upon the mind, 

 of contact with, and contemplation of the phenomena of 

 nature ; but it is not the great and sublime objects of 

 nature alone that produce this effect the sublimity 

 of mountains, the majesty of rivers, and the repose of 

 forests, the very humblest and simplest objects are cal- 

 culated to awaken these emotions in a yet higher and 

 purer form. " The microscope," as Mr. Lewes has well 



