PREFACE 



ALTHOUGH during recent years considerable additions have 

 been made to our elementary botanical textbooks, not one 

 has appeared which deals solely, or at any length, with the 

 subject of vegetable physiology. This has been either 

 presented to the reader as a particular section in a com- 

 prehensive work, or treated of incidentally in connection 

 with anatomical detail. This is the more strange, as an 

 adequate and intelligent appreciation of the forms and 

 structure of vegetable organisms can only be gained by a 

 consideration of the work they have to carry out. It must 

 be evident to the student of Nature that the peculiarities 

 of external and internal form, of which any particular plant 

 has become possessed, have arisen necessarily in con- 

 nection with the need of mechanisms to do certain work, 

 to overcome particular disadvantages, and generally to 

 bring the organism into a satisfactory relationship with the 

 surroundings among which it finds itself. 



I have been led by these considerations to endeavour to 

 fill this gap by writing an introduction to the subject, 

 which, while putting physiology into its proper prominence 

 among the branches of botanical study, shall serve to pave 

 the way of the student and of the general reader to the 

 more complete discussion of the subject which may be met 

 with in the advanced textbooks of Sachs, Vines, and 

 Pfeffer. 



I O O f\ A Q 



