PREFACE xi 



One may well feel inclined to ask : ' What must 

 educated men think of a Berlin Professor who 

 seriously gives utterance to such fantastic ideas ? ' 

 Can Dr. v. Hansemann fail to see that his words 

 contain a serious insult to his colleagues at the 

 University of Berlin, who signed the invitation 

 to my lectures, and so apparently helped to ensnare 

 finches ? We receive, moreover, a strange impres- 

 sion of scientific toleration, when von Hansemann 

 demands not only that people, whose views differ 

 from his own, should be forbidden to speak, but that 

 they should actually be excluded from the country. 



The present work is divided into two parts. The 

 first part contains the three lectures given in Berlin. 



The second part contains a report of the evening 

 discussion, with critical remarks. 



The lectures in Part I. were taken down in short- 

 hand with the greatest possible accuracy, and these 

 shorthand notes, in somewhat abbreviated form, 

 appeared in the Germania, Nos. 38, 39, 41. A long 

 passage in the first lecture, which was illustrated by 

 fifty-six lantern slides, is necessarily much condensed, 

 as the illustrations cannot be reproduced here. Any 

 one who takes an interest in the facts represented 

 can find detailed information and diagrams relating 

 to them in the tenth chapter of the 3rd edition of 

 my book entitled Modern Biology and the Theory 

 of Evolution, Freiburg i. Br., 1906. 1 



1 I shall refer to this work henceforth as The Modern Biology. 



