GENERAL INTRODUCTION 



SACHS has pointed out in his History of Botany how great 

 was the change in the position of investigation and study 

 which took place towards the middle of the last century. 

 After 1840 there set in a great modification of botanical 

 literature ; instead of weighty presentations from the hands 

 of a succession of great masters appearing at long intervals, 

 the subject was developed by single monographs or isolated 

 memoirs coming from the pens of numerous writers 

 from various centres of study. These were naturally of 

 very unequal merit, and needed a careful and indepen- 

 dent scrutiny from their readers. The weight of authority 

 was thus disturbed and the critic rather than the student 

 grew in apparent importance. This change in the history 

 of the development of the science became more and more 

 pronounced as the century advanced ; a period of con- 

 fusion arose, which was perhaps inseparable from the 

 accumulation of masses of detail concerning intricacies of 

 form and structure. Out of such accumulations, however, 

 though they were marked for the most part by no plan 

 and no orderly arrangement, definite principles slowly 

 emerged and made clear the way for the observers from 

 1860 onwards. At the outset, we find the researches 

 of that time failed especially to recognize the funda- 

 mental importance of the study of the living processes 

 of the plant, of the bearing of anatomy on physiology 

 and of physiology in its turn on anatomy : structure and 

 function were only partially correlated and there was little 

 recognition of the fact that the clue to the meaning of 



