270 OPERATIONS SUBSIDIARY TO INDUCTION. 



them from vagueness by giving them a definite conno- 

 tation) as generic terms, subdividing the genera into 

 species. 



4. While the more rapid growth of ideas than 

 of names thus creates a perpetual necessity for making 

 the same names serve, even if imperfectly, on a 

 greater number of occasions; a counter-operation is 

 going on, by which names become on the contrary 

 restricted to fewer occasions, by taking on, as it were, 

 additional connotation, from circumstances not origi- 

 nally included in the meaning, but which have become 

 connected with it in the mind by some accidental 

 cause. We have seen above, in the words pagan and 

 villain, remarkable examples of the specialization of 

 the meaning of words from casual associations, as well 

 as of the generalization of it in a new direction, which 

 often follows. 



Similar specializations are of frequent occurrence 

 in the history even of scientific nomenclature. " It 

 is by no means uncommon," says Dr. Paris, in his 

 Pharmacologia* , " to find a word which is used to 

 express general characters subsequently become the 

 name of a specific substance in which such characters 

 are predominant; and we shall find that some im- 

 portant anomalies in nomenclature may be thus ex- 

 plained. The term Apo-eviicov, from which the word 

 Arsenic is derived, was an ancient epithet applied to 

 those natural substances which possessed strong and 

 acrimonious properties, and as the poisonous quality 

 of arsenic was found to be remarkably powerful, the 

 term was especially applied to Orpiment, the form in 

 which this metal most usually occurred. So the term 



* Historical Introduction, vol. i., pp. 66-8. 



