THE VITAL FORCE. 63 



holding them as it were in partial check, and causing 

 the chemical tendencies to fall short of their full 

 satisfaction. Nor is the power of limiting the chemi- 

 cal processes on the part of organic bodies a mere 

 supposition : it is a power which they are known to 

 possess, which is indeed one of their most obvious 

 and familiar properties. Living bodies are distin- 

 guished by their resisting to some extent the opera- 

 tion of chemical forces ; and to this resistance their 

 power of causing chemical change to produce 

 living matter may be referred. When the forces 

 are too great, and overcome the resistance, then 

 there results from them only decomposition. They 

 run on to the destruction of the organic state, and the 

 dissipation (in heat or other inorganic forms) of the 

 force that it embodied. 



It thus appears that the origination of organic Life 

 in Nature remains an open question. Our knowledge 

 extends at present only to its reproduction and in- 

 crease. To these there is a sufficient key in well- 

 known laws ; and they may be carried to any extent 

 without demanding the supposition of other than 

 familiar agencies and established principles. But the 



