^6 PBOCEEBINGS OF THE 



three hundred. As a lecturer, Weismann had exceptional 

 powers: bis annual course on the theory of Evolution, which 

 was not confined to students of the University, attracted large 

 audiences. 



Apart from Weismann's earlier researches, which included 

 many important contributions to histology and embryology, his 

 life's work was dominated by a central idea — first clearly indicated 

 in his papers on the sexual cells of the Hydrozoa — that of 

 following out his ideas on evolution, based on selection, to their 

 logical outcome. He attempted to build up a theory of heredity 

 wliich was not to be looked upon as "a structure calculated for 

 eternity, but as one which should serve as a solid nucleus — a 

 crystallization-point — for further research, and around which new 

 acquisitions in knowledge should group themselves for a time" 



a theory which should be capable of " modification without 



giving up its fundamental principles." Thus the theory of the 

 " germ-plasm " was gradually evolved, and eventually led up to 

 that of " germinal selection " and to further arguments against 

 the belief in the transmission of somatic modifications. He 

 rarely entered into controversy, one of the few exceptions being 

 his replies to Herbert Spencer in the ' Contemporarj^ Review ' in 

 1894-5. 



The preparation of a third edition of the " Yortrage liber 

 Desceudenztheorie " involved a great amount of work and was 

 a heavy strain upon the author, as much new matter relating to 

 his own theories as well as to important researches which had 

 appeared since the previous edition (e. g. those dealing with 

 Mendelism) had to be incorporated. It appeared in 1913, and 

 may be looked upon as a summary of Weismann's life's 

 work. 



His seventieth birthday was celebrated in Freiburg by the 

 presentation of a " Festschrift " and of a bust, subscribed to by 

 Biologists from many countries, which has been placed in the 

 Zoological Institute. On this occasion, he gave a short account 

 of his career. 



"Weismann, on whom, it has been said, Darwin's mantle 

 had fallen, contributed an essay to the Cambridge Volume on 

 " Darwin and Modern Science " in 1909 : the following translation 

 of a passage taken from his address at Freiburg in connection 

 with the Darwin Centenary Celebration, is interesting as giving 

 some idea of his views on the ethical bearings of evolution : — 



"The human race will never consist of entirely unselfish 

 saints ; but I believe that the immber of those who act on the 

 basis of a purer and higher humanity and in whom the care for 

 the whole race overshadows that of self, will increase as time 

 goes on, as we know it has done in the past and has led to 



higher forms of religion and to higher ethical conceptions 



The theory of evolution has often been perverted so as to 

 indicate tliat what is merely animal and brutal must gain the 

 ascendancy. The contrary seems to me to be the case, for in 



