22 INTRODUCTION. 



merating all the individual contents or the characteristics of 

 these groups is avoided. Thus the single word Ruminantia 

 stands for- camels, lamas, giraffes, deer, antelopes, goats, sheep, 

 and kine, or for all the hoofed quadrupeds which ruminate 

 or chew the cud, and have no front teeth in the upper jaw ; 

 Lejridoptera includes all the various kinds of butterflies, hawk- 

 moths, and millers or moths, or insects having wings covered 

 with branny scales, and a spiral tongue instead of jaws, and 

 whose young appear in the form of caterpillars. It would be 

 difficult to find or invent any single English words which 

 would be at once so convenient and so expressive. This, 

 therefore, is an additional reason why scientific names ought 

 to be preferred to all others, at least in works of natural his- 

 tory, where it is highly important that the objects described 

 should have names that are short, significant in themselves, 

 and not liable to be mistaken or misapplied. 



There is no art, profession, trade, or occupation, which can 

 be taught or learned without the use of technical words or 

 phrases belonging to each, and which, to the inexperienced 

 and untaught, are as unintelligible as the terms of science. 

 It is not at all more difficult to learn and remember the latter 

 than the former, when the attention has been properly given 

 to the subject. The seaman, the farmer, and the mechanic 

 soon become familiar with the names and phrases peculiar to 

 their several callings, uncouth, and without apparent signifi- 

 cation, as many of them are. So, too, the terms of science 

 lose their forbidding and mysterious appearance and sound 

 by the frequency of their recurrence, and finally become as 

 harmonious to the ear, as they are clear and definite in their 

 application. 



