48 



Nor are we, in associating the manifestations of life 

 vith the operation of external forces, required to dis- 

 cuss the nature of the so-called vital force as distinct 

 from other forces, though we cannot help remarking 

 that hitherto too broad a line of demarcation has 

 been drawn between it and the other operating forces 

 of the universe. Whatever the vital force may be, it 

 never manifests itself save in connection with, or 

 under the operation of, other forces. If it be some- 

 thing per se, it clearly can neither assert its presence 

 nor continue its existence independent of other forces ; 

 and seeing the vast progress that has been made 

 during the current century in our knowledge of the 

 subtlest powers in nature — heat, light, actinism, 

 magnetism, galvanism, and electricity — we cannot 

 suppress the hope that science will ere long be enabled 

 to do something more than merely give a name to the 

 most interesting of natural phenomena. 



It has also been argued — and the argument is by 

 no means foreign to the inquiry — ^that if there be a 

 process of modification in nature, by which the higher 

 is developed from the lower, the isrocess must embrace 

 the mental as well as the physical organisation of the 

 creature so developed. This argument embodies, of 

 course, the old question of instinct and reason, or in 

 other words, whether the guiding power of the lower 

 animals be a thing sui generis, and distinct from 



