PREFACE. 



THE following attempt at a popular exposition 

 of a subject almost unknown in this country, 

 originated in a series of short articles in Nature, 

 and when the publishers proposed that I should 

 add to these and cast them into the form of a 

 book, I assented with the more pleasure because 

 it afforded an opportunity of calling attention to 

 several points well worth further investigation. 



Had my primary object been to write a treatise 

 on the whole subject of the diseases of trees, 

 I should have adopted a somewhat different plan, 

 and discussed many of the phenomena at greater 

 length. 



Chapter IV. will perhaps be regarded as too 

 technical for the general reader, but it seemed 



