4 BIOLOGICAL LECTURES. 



made the distinction between a living and a dead thing to con- 

 sist in the presence of a force radically different from all other 

 forces, which presided for the time in much the same way as 

 Kepler's guiding spirits presided over planetary motions. 



We know what the history of such prepossessions has been. 

 A hundred years ago Caloric was thought to be such an im- 

 ponderable potency, Light was thought to be another, Electric- 

 ity still a third. Each of these turned out to be no impondera- 

 ble at all but simply physical properties of matter of the ordi- 

 nary sort. But the change from the old to the new view in 

 these matters made it needful to change the fundamental ideas 

 concerning matter itself. 



The physiologists for a generation have ceased to think of a 

 vital force as different from other forces in the same way as 

 they have ceased to consider light as an emanation. And the 

 consensus of opinion among biologists, if one may judge from 

 a multitude of expressions by them concerning life, is that all 

 the phenomena exhibited by a living thing are finally resolvable 

 into physical and chemical processes. 



A vital element peculiar to organisms no more exists than does a 

 vital force working independently of natural and material processes. 

 — Clans afid Sedgwick. 



It must not be supposed that the differences between living and 

 not living matter are such as to justify the assumption that the 

 forces at work in the one are different from those to be met with in 

 the other. — Huxley. 



Zoology, the science which seeks to arrange and discuss the 

 phenomena of animal life and form as the outcome of the operations 

 of the laws of physics and chemistry. — Lankaster. 



Certain it is that life is a chemical function, says Prof. Stokois, 

 of Amsterdam, and he adds, Is not the chemical function a sort of 

 life? 



So vital force as a distinct somewhat invented to account 

 for living phenomena, has now no status anywhere. If it be 

 so, then it is plain that matter has properties which have not 

 been included in its list. If matter has been defined as inert, 

 or as dead or as inanimate, one may have to revise his defini- 

 tion. Is it not plain in an a priori way that the phenomena 



