STUDIES IN ANIMAL LIFE. 87 



mals, living and extinct, as a student is with the as- 

 pect of editions. Yet, before that knowledge could 

 have been acquired, before he could say thus confi- 

 dently that the tooth belonged to an extinct species 

 of rhinoceros, the united labors of thousands of dili- 

 gent inquirers must have been directed to the clas- 

 sification of animals. How could he know that the 

 rhinoceros was of that particular species rather than 

 another? and what is meant by species? To trace 

 the history of this confidence would be to tell the 

 long story of zoological investigation ; a story too 

 long for narration here, though we may pause a 

 while to consider its difficulties. 



To make a classical catalogue of the books in the 

 British Museum would be a gigantic task ; but 

 imagine what that task would be if all the title- 

 pages and other external indications were destroy- 

 ed ! The first attempts would necessarily be of a 

 rough approximative kind, merely endeavoring to 

 make a sort of provisional order amid the chaos, 

 after which succeeding labors might introduce bet- 

 ter and better arrangements. The books might first' 

 be grouped according to size ; but, having got them 

 together, it would soon be discovered that size was 

 no indication of their contents : quarto poems and 

 duodecimo histories, octavo grammars and folio 

 dictionaries, would immediately give warning that 

 some other arrangement was needed. Nor would 

 it be better to separate the books according to the 

 languages in which they were written. The pres- 



