ON THE VITALTSTIC VIEW OF NATURE. 405 



of his life never satisfied himself that the phenomena of 23. 



Liebig's 



life can be mechanically explained : he remained, in the vitalism - 

 face of much criticism, a Vitalist. So did Wohler in 

 Germany so did most of the eminent physiologists in 

 Trance and in England. The crusade against Vitalism, 

 which was started in Germany, seems to have had little 

 influence on them. In 1854, six years after Du Bois- 

 Eeymond's essay on Vital Force, and twelve years after 

 that of Lotze, Huxley 1 could still, in the first of his 

 ' Lay Sermons ' " On the educational value of the natural 

 history sciences," express opinions on the difference be- 

 tween living and not-living bodies which were distinctly 

 vitalistic, maintaining, much in the same way as Liebig 

 did in the later editions of his chemical letters, that "the 

 phenomena of life are dependent neither on physical nor 

 on chemical, but on vital forces"; and if, in 1870, he 

 could himself state that he had long since grown out 

 of this view, it is interesting to discover what were 

 the arguments which brought about this remarkable 

 change. I will at once state what seems to me to be 

 the great influence which combated Vitalism in this 

 country, which greatly strengthened the anti-vitalistic or 

 mechanical views in Germany, but which, as little as the 

 mathematical and philosophical criticism of Lotze and 

 Du Bois-Reymond, ever took real hold of biological thought 



inquiry hitherto entered on. About 

 twenty -five years ago I asked 

 Liebig if he believed that a leaf or 

 a flower could be formed or could 

 grow by chemical forces. He 

 answered, I would more readily 

 believe that a book on chemistry 

 or on botany could grow out of 

 dead matter by chemical processes." 



printed in 1870 in the well-known 

 volume, entitled ' Lay Sermons, 

 Addresses, and Reviews,' with a 

 " prefatory letter " to Tyndall, 

 in which the following passage 

 occurs : " The oldest essay of the 

 whole contains a view of the nature 

 of the differences between living 

 and not-living bodies, out of which 



1 The address referred to was re- i I have long since grown." 



