266 A LIBRARIAN'S WORK. [xn. 



problem to one who has mastered the theory on which 

 the catalogue is constructed, at the same time make 

 it the more unmanageable to any one who has not 

 done so. To assign to any title its proper position, 

 you must not merely know what the book is about, 

 but you must understand the reasons, philosophical 

 and practical, which have determined the place to 

 which such titles have already been assigned. It is 

 a case in which no mere mechanical following of tradi- 

 tion is of any avail. No general rules can be laid 

 down which a corps of assistants can follow ; for in 

 general each case presents new features of its own, so 

 that to follow any rule securely would require a mental 

 training almost as great as that needed for making 

 the rule. Hence when different people work inde- 

 pendently at a classified catalogue, they are sure to 

 get into a muddle. 



Suppose, for example, you have to classify a book 

 on the constitution of Massachusetts. I put such 

 books under the heading " LAW Mass. Const.," 

 but another person would prefer " LAW Const. 

 Mass.," a third would rank them under "LAW U.S. 

 Const. Mass.," a fourth under "LAW U.S. 

 (Separate States) Mass. Const." a fifth under 

 " LAW Const. U.S. Mass.," and so on, through 

 all the permutations and combinations of which these 



