324 BIOLOGY 



know, no method of origin except from previously existing life. 

 We must look at life as a unique manifestation of force, stand- 

 ing by itself. This is perfectly consistent with the recognition 

 of the fact that the animal body is a machine, acting in accord- 

 ance with the principles of conservation of energy, and that 

 a living organism simply transforms one type of energy into 

 another. This view is also equally consistent with the sug- 

 gestion that there is a special force, which we call life, directing 

 the activity of these machines. At all events, for the present 

 we can go no farther in the discussion of the question than this. 

 Life is the directive agent which controls the activity of the 

 living machine, and death means the disappearance of this 

 controlling agent; though what is meant by its disappearance 

 we cannot say, any more than we can tell what caused its 

 appearance in the machine in the first place. The question of 

 the real significance of life and death is still unanswered by 

 science. 



