AUTHOR'S PREFACE 



Twenty-five years have passed since the appearance of Hermann 

 Muller's admirable book on 'The Fertilisation of Flowers by Insects and 

 their Reciprocal Adaptations ^' It has long been out of print, and it 

 seemed to me to be worthy of republication with notes, like the funda- 

 mental work of Christian Konrad Sprengel : Das entdeckte Geheimnis <kr 

 Natur itn Bau und in der Befruchtung der Blumen (Berlin, 1793), which 

 I brought out some years ago in Ostwald's Klassiker der exakten Natur- 

 wissenschaften (vols, xlviii-li) 2. The further, however, I entered into the 

 subject, the more I became convinced that the observations of later 

 investigators, following in the steps of Miiller during the Icist two decades, 

 and developing this branch of botany in a remarkable manner, have given 

 us such abundance of new material that the necessary notes and additions 

 would considerably exceed the original contents of Muller's book. I accord- 

 ingly resolved to write an entirely new work, founded upon Hermann 

 Muller's ' Fertilisation of Flowers by Insects,' after satisfactory arrangements 

 had been made with his representatives. 



The fruitfulness of the investigations made during the last two decades 

 on the relations between the structure and environment of flowers, and 

 the widening of the circle of those who take an active part in these 

 investigations, have added to the difficulty of the task of collating the 

 enormous quantity of available material. To accomplish this it was 

 necessary to devote three years of uninterrupted labour, during which there 

 appeared numerous, and in part extremely important, new publications on 

 Flower Pollination, which had to be taken into consideration. Literary 

 activity, however, quite unlike scientific investigation, demands a conclusion, 

 and therefore it seemed to me inexpedient to delay any longer the 

 publication of the work. The memoirs that appeared on the subject 

 during the printing of my work were considered as far as possible, 

 especially when they afforded a solution of contradictions occurring in 

 the statements of different observers in regard to the same flower. During 

 the whole time spent in writing this work, I have been constantly engaged 



* 'Die Befruchtong der Blumen durch Insekten und die gegenseitigen Anpasiungen beider, 

 Leipzig, 1873, Wilhelm Engelmann. English Translation by D'Arcy W. Thompson, 1883. 

 ' Leipzig, 1894, Wilhelm Engelmann. 



