TRANSLATOR'S PREFACE. 



In introducing to the English public Sachs's ' Lehrbuch der Botanik ' in an 

 English form, the translator believes that he is supplying a want which has long 

 been felt by English botanical students. Our own Hterature has not at present 

 produced any work at once so comprehensive in its scope and so minute and 

 accurate in its details, — qualities which have recommended the German work to 

 every one familiar with that language. 



In the notes the citations of authorities have been somewhat increased. It has 

 also seemed desirable sometimes to depart from the author's rule of passing over 

 authorities whose interest is now chiefly historical. References have been given 

 to English and French translations of many of the papers and memoirs quoted, 

 as these are at any rate often more accessible in this country than the originals. 



On several points additional matter has been introduced into the footnotes. 

 With respect to these the translator has to acknowledge the kind help of numerous 

 scientific friends, amongst whom he may more especially mention Professor W. C. 

 Williamson, Mr. H. C. Sorby, and Professor W. R. M^Nab. In the selection of 

 English expressions for German technical terms he has also in many instances had 

 recourse to their advice. One case of great difficulty may be pointed to in ' Stoff- 

 wechsel'; as an equivalent to this the term * Metastasis' has been used. It had 

 already been employed in a more restricted although analogous way by Graham; 

 speaking of the mutability of colloids due to internal molecular rearrangements, 

 that distinguished chemist says, ' Their existence is a continued metastasis ' (Journ. 

 Chem. Soc. 1862, p. 217). 



The fourth edition of the German work has been passing through the press 

 concurrently with the printing of this edition. Where possible the new matter 

 introduced into it, or the new views adopted by the author^ are referred to in 

 the footnotes to the present edition. The new classification of Cellular Crypto- 

 gams adopted by Sachs will be found at p. 847. 



A. W. B. 



London, February 1875. 



