50 WHAT IS LIFE 



one kicked it, i.e., its motion was passive. What 

 made the mouse move ? Let us suppose that it 

 was because it saw a cat. Then its movement was 

 active. Not so, says M. Le Dantec, as we must 

 suppose from the opinions which he expresses, the 

 presence of the cat exercises a tactic influence 

 upon the mouse which obliges it to move, but its 

 movement is not an active one but as passive as 

 that of the stone. As far as the present writer can 

 see the above is a fair statement of the views now 

 under consideration. 



If this is the case, however, there is one thing 

 quite clear, namely that the tactic influence must 

 work always and unerringly and altogether apart 

 from any influence which the mouse may be sup- 

 posed to be able to exhibit, granting for a moment 

 that it could, if the passive sport of tactisms, ex- 

 ercise any influence over itself or anything else. 

 This at least is clear, for the rigid unbending rules 

 of chemistry and physics would make it impossible 

 for any departure to arise from the regular series 

 of events involved in a chemical or physical process. 

 We may grant that a mouse does usually or even 

 invariably fly from a cat when it sees one. The 

 reaction regularly occurs. But we cannot be at 

 all sure that if a cat was introduced for the first 

 time into an island inhabited by mice that they 

 would fly from it. So far as the present writer 



