Vlll PREFACE. 



lation was published in 1887 by the Clarendon Press 

 under the title Lectures on the Physiology of Plants.] 



Gesammelte Ahhandlungen ilber Pflanzen-Physiologie 

 von Julius Sachs. Leipzig, Engelmann. Band I. 1892, 

 Band ii. 1893. [This is referred to in the text as Sachs' 

 Collected Papers^ 



I gladly take this opportunity of expressing my thanks 

 to Mr F. F. Blackman, Demonstrator of Botany in the 

 University, for much valuable help in the arrangement of 

 the experiments in Part I. Also to the Cambridge 

 Scientific Instrument Company for the use of the cliches 

 for Figs. 25 and 26. 



FRANCIS DARWIN. 



Botanical Laboratory, Cambridge. 

 September, 1895. 



