52 WHAT IS LIFE 



wholly unknown to chemistry and physics, one 

 which can only be explained on the ground that 

 the birds were possessed of a sense not belonging 

 to non-living matter. The only other explanation 

 is that the contact with man caused such an 

 alteration in the colloids of the sea-birds* bodies 

 that a different re-action took place after some 

 time of acquaintance to that which was first ex- 

 hibited and such an explanation only needs to be 

 formulated for its absurdity to be seen. 



We may fairly claim then that though many 

 phenomena exhibited by living things may be 

 explained as tactisms, and as re-actions to certain 

 chemical or physical forces, it is not possible to 

 explain all the phenomena of life or of irritability 

 in these terms. 



