BOTANICAL BOOKS AND THEIR USE 125 



popular works, and through these to many that are of 

 little or no value. I have not myself given attention to 

 the popular books, but there are references to a few 

 of the best in L. H. Bailey's "Lessons with Plants," 



P- 443- 



Passing next to the important subject of reference 

 books, I shall enumerate the best in each department 

 of work likely to be taken up in an elementary course. 

 Reference books have several purposes for the teaching 

 botanist : they are sources of information when new 

 points come up on which information is needed ; they 

 supply new methods in manipulation when new subjects 

 are taken up ; they are full of suggestions to the brighter 

 students who take pleasure in looking through them ; 

 and they supply illustrations and additional subject- 

 matter for fuller treatment of particular topics. They 

 should always be accessible in the laboratory, and 

 students should be encouraged to use them constantly, 

 following up through the indexes the topics in which 

 they may be interested. This habit of constantly con- 

 sulting the literature is a most important one to cultivate 

 in students. Where a school library cannot afford all 

 of these books, but can buy some, the first mentioned 

 under each of the classes here described should be 

 selected. Text-books will be considered by themselves 

 later. The following list is, of course, not intended to 

 be exhaustive, but simply to include the most recent 

 and authoritative works. The science is advancing so 



