PREFACE TO THE SECOND EDITION. 



| HE preparation of the First Edition was an experi- 

 ment, as there was some doubt as to the demand for 

 such a book and considerable uncertainty as to how 

 many people would be able to use it successfully. 

 The sales of the First Edition have proved con- 

 clusively the demand for a book of this kind, and it has 

 also been proved that the hand-lens can be successfully used 

 to determine a much larger number of mosses than was included 

 in the First Edition. This is shown by the readiness with which 

 persons of no special scientific training have identified the com- 

 mon mosses by its use. 



By the use of slides prepared as for the compound micro- 

 scope, and the very best lenses such as are advertised in the last 

 pages of this book; many characters which were little or not at 

 all used in the First Edition can be utilized in determining diffi- 

 cult species. Such characters are the gross structure of the per- 

 istome, the characters of the costa, and the margins of the leaves, 

 position of the reproductive organs, and in many cases the gen- 

 eral outline of the cells. 



The hand-lens can never equal the compound microscope for 

 making out these finer details of structure, but the compound 

 microscope is beyond the reach of many who would gladly study 

 the mosses if it can be done with a hand-lens. No characters 

 have been utilized which the author has not been able to make 

 out with his lens, but it may easily be true that the beginner may 

 not*be able to see as much at first. The author believes that the 

 limit of utility of the hand-lens has been reached in this edition, 

 so far as the mosses are concerned at least. The section on the 

 Hepatics is less complete owing to the limitations of the author. 



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