180 THE NATURE AND ORIGIN OF LIFE 



Nerve conduction is nothing else than conduction by 

 protoplasmic continuity. It manifests itself in any cell 

 at all, but its effects are more curious when the cell is very 

 long drawn out. 



Consider (Fig. 12) a long cell A, B bathing in a different 

 colloid from itself. If you produce at point A a rupture of 

 the colloid equilibrium, this rupture of equilibrium will 

 be transmitted from point to point on to B, where we can 



verify its effects. This does 

 not prevent the rupture of 

 equilibrium at A from having 

 its rebound also in the colloid 

 surrounding the cell and mak- 

 ing itself felt at the external 

 point C ; but observation 

 shows that its influence at B 

 FIG. 12. is vastly more important from 



the continuity of homogeneous 

 protoplasm. We verify the fact without trying to explain 

 it, just as we verify in Morse telegraphy with naked wire 

 that the effect transmitted by the conducting wire is much 

 more considerable at the end of the wire than at any point 

 of the surrounding air. 



Experiments in merotomy make us understand the 

 importance of protoplasmic continuity. After cutting a 

 cell in two, the fragment deprived of nucleus still exists 

 in the same drop of infusion as the nucleated fragment, 

 but it does not experience in the infusion the beneficent 

 influence of the nucleus. This makes itself felt by proto- 

 plasmic continuity only within the nucleated fragment, 

 where assimilation consequently still goes on. 



We can only verify the fact, but it does not surprise us. 

 We are accustomed to recognize in physics the great import- 



