LIFE AS COMPARED WITH THE PHYSICAL FOECES. 57 



US, points to the vital forces being unique, not comparable to or 

 interchangeable with other forces of energy. But while this is 

 true, I should not care to build any theological superstructure 

 upon such a basis. An argument ivora ignorance is at any 

 moment liable to be overturned by the discovery of fresh facts. 

 The origiTi of thought, rather than the origin of life, is the point 

 at which we come upon an impassable barrier, not merely a barrier 

 that has never yet been crossed. 



