THE LAWS OF LIFE. 237 



acting, in the same direction, the upward movement 

 is proportionately greater. Thus the vital action 

 which ensues from any given chemical change may 

 have added to it, as it were, the momentum of 

 whatever forces can add their impetus to the 

 molecular movement which constitutes the chemical 

 changdr 



How much of heat, or light, or electricity comes 

 thus to assume the form of vital action, may perhaps 

 be estimated by the amount of the absorption of 

 those forces which may be found to accompany the 

 vital processes. 



But to embrace all the phenomena contained in 

 even the simplest idea of life, regarding it, that is, 

 as the mere bringing into existence of organic 

 matter, it is necessary to extend somewhat the con- 

 ception I have suggested. In the vibration of a 

 pendulum the same portion of matter falls, and rises 

 again by virtue of its fall. But a falling body 

 may impart its momentum, and, not rising itself, 

 may cause in other matter a proportionate upward 

 movement. The requisite mechanism is simple, and 

 involves only the one condition, that the body re- 



