

PREFACE 



Plant-physiology has been enriched by contributions to 

 knowledge made by a succession of eminent and devoted 

 workers. In regard to my own investigations on the subject, 

 it may not be out of place to state that, being originally 

 intended for the profession of medicine, I had the great 

 ■advantage of pursuing at the University of Cambridge 

 the study of the life-reactions of both plants and animals. 

 Since then two subjects have claimed my closest attention — 

 the physics of inorganic and the physiology of living matter. 



Being at one time called upon to teach physiology of 

 plants to a student preparing for a University degree in 

 Science, the various questions raised by the unsophisticated 

 mind of my pupil led me to realise that some of the theories 

 which I had passively imbibed in my student days were 

 by no means infallible. I also came to recognise that the 

 main difficulty which stood in the way of deeper knowledge 

 was the absence of sufficiently sensitive means for detecting 

 the internal activities of plant-life. I therefore devoted many 

 years to the invention and construction of various Auto- 

 matic Recorders of extreme delicacy and precision, which 

 enable the plant itself to write down the inner workings 

 of its life. 



Unfounded speculation has often obstructed the advance 

 of knowledge ; facts must supersede speculation, for it is 

 not the preconceived bias of the observer, but unimpeach- 

 able facts that alone can lead to the establishment of sound 

 theory. This accounts for the attitude of detachment 

 that I maintained for many years. In the preface to my 



