PREFACE. 



THE absence of any text-book in the English language 

 treating at all fully of the Physiology of Plants, so as 

 to meet the requirements of advanced students, sug- 

 gested to me, at an early stage in my career as a 

 teacher of the subject, that I should publish my own 

 lecture-notes just sufficiently expanded to make them 

 readable. Of this suggestion, this volume is the out- 

 come. The work of preparation began in 1877, but, 

 on account of the pressure of other duties, it was not 

 until 1882 that it had proceeded far enough to warrant 

 going to press. I hoped at that time to have com- 

 pleted the Lectures within a twelvemonth at longest, 

 but failing health and increasing demands upon my 

 time have extended the period to four years. In con- 

 sequence of this delay, it will be found that in the 

 earlier Lectures the most recent researches have^iot 

 been noticed. There will, I hope, be an opportunity 

 to remedy this defect in a subsequent edition. 



There is one point to which I would especially 

 draw the attention of the reader, namely, to the use of 

 the terms " dorsal" and " ventral" in speaking of the 



