PREFACE TO THE FIFTH ENGLISH EDITION. 



THE present edition of this work has been rewritten almost 

 throughout. In doing this full use has been made of the 

 third edition of the Author's Das Botanische Praktikum, which 

 appeared in 1897. A number of new figures have been 

 introduced, the most important of which are a series dealing 

 with the histology of Tilia and of Pinus. 



As far as possible I have endeavoured to avoid conten- 

 tious matter, believing such to be out of place in a book 

 of this kind ; but it must be borne in mind that the " facts " 

 of a science such as Botany are to a large extent inferences 

 or interpretations, so that sources of contention cannot be 

 entirely eliminated, and new ones are at any time liable 

 to arise. It has been a matter of difficulty to determine 

 to what extent certain varying interpretations should be 

 recognised, and in some cases, in endeavouring to avoid 

 possible confusion in the mind of the student, I have perhaps 

 gone astray, as, for example, in retaining the old term 

 "vessels" for many structures the trache'idal character of 

 which is now generally accepted. 



As the practical advantages appeared to warrant it, the 

 numerous notes derived from my own laboratory practice, 

 and other sources, which had been introduced into the 

 earlier editions, or are new to this, have now as a rule been 

 fully incorporated with the text. The curious in such mat- 

 ters can doubtless disinter them by a comparison of the first 

 English edition (in which all such additions were in square 

 brackets), and of the German third edition, with the present 

 issue. 



After careful consideration I have omitted the biblio- 

 graphical notes which were appended to the chapters. As the 



