194 THE PHENOMENA OF MOTION 



manifested in itself, must have a momentum of motion, 

 which is nothing else than the measure of the resulting 

 motion or change in form and structure. 



We know that this momentum of motion in the vital 

 force, residing in a living part, may be employed in 

 giving motion to bodies at rest (that is, in causing de- 

 composition, or overcoming resistance), and if the vital 

 force is analogous in its manifestations to other forces, 

 this momentum of motion must be capable of being 

 conveyed or communicated by matters, which in them- 

 selves do not destroy its effect by an opposite manifes- 

 tation of force. 



Motion, by whatever cause produced, cannot in it- 

 self be annihilated ; it may, indeed, become inappre- 

 ciable to the senses, but even when arrested by resist- 

 ance (by the manifestation of an opposite force) its 

 effect is not annihilated. The falling stone, by means 

 of the amount of motion acquired in its descent, pro- 

 duces an effect when it reaches the table. The im- 

 pression made on the wood, the velocity communicated 

 by its parts to those of the wood, all this is its 

 effect. 



If we transfer the conceptions of motion, equili- 

 brium, and resistance, to the chemical forces, which, 

 in their modus operandi, approach to the vital force 

 infinitely nearer than gravitation does, we know with 

 the utmost certainty, that they are active only in the 

 case of immediate contact. We know, also, that the 

 unequal capacity of chemical compounds to offer re- 



