PREFATORY NOTE. 



to the attempt to frighten sober people by the sugges- 

 tion that evolutionary speculations generate revolu- 

 tionary schemes in Socialist brains. But then the 

 authors of the " Rejected Addresses " were joking, 

 while Professor Virchow is in grim earnest ; and that 

 makes a great difference in the moral aspect of the 

 two achievements. 



