134 THE SIGNS OF LIFE [LECT. 



kathode kataphoresis is a chief factor in the electrical osmose 

 first made known to us by the investigations of Ouinke. 



Our attention is naturally directed to the question of such 

 water transport through porous bodies by a very remarkable 

 diminution of resistance that occurs in skin, in leaves, etc. as 

 a consequence of the passage of induction shocks. This diminu- 

 tion of resistance, or augmentation of conductivity, is far more 

 pronounced in living than in dead matter, and a diminution of 

 resistance in consequence of molecular dissociation of active 

 stuff must therefore be thought of. 



I think it probable that both factors contribute to the result ; 

 their experimental distinction and separate examination appears 

 very desirable, but very difficult. 



It is indeed easy enough to witness what must be an effect 

 of kataphoric water movement on an inert object, such as an 

 eggshell ; it is the distinction between effects of kataphoresis 

 and a dissociation on a living object that is difficult. The best 

 thing that can be hoped for, is to find cases where one factor is 

 predominant and the other insignificant. In a muscle, e.g., we 

 may expect to get most distinct evidence of dissociation ; Loeb* 

 has, in fact, shown that the osmotic pressure of muscle is con- 

 siderably augmented by tetanisation, resting muscle being 

 isotonic with a 0.6 per cent. NaCl solution, tetanised muscle 

 with a i.o per cent, solution. We should accordingly expect to 

 find 'an increased conductivity in active muscle, perhaps also in 

 active nerve as was supposed to be the case by Griinhagen. I 

 have not yet found time to carry out such experiments ; perhaps 

 someone among my present hearers will take them in hand. 



The following experiment has been put up to show this 

 purely physical effect of kataphoresis ; it will at the same time 

 serve to illustrate another of the fallacies that might deceive an 

 inexperienced observer. 



An eggshell (with its membrane) has been set up between 

 the exploring electrodes to be examined in the usual way. 

 From a compensator I pass T ^ volt through the shell and 

 galvanometer ; the deflection is \ degree of scale. I pass 



* Loeb, " Physiologische Untersuchungen iiber lonenwirkungen (I Ver- 

 suche am Muskel)," Pflitge^s Archiv, Ixix., p. i, 1898, and Ixxi., p. 457. 



