262 COMPARATIVE ELECTRO-PHYSIOLOGY 



previous chapters to be quite untenable. I shall presently 

 describe experiments which will further show that galvano- 

 metric responses, not to be distinguished from this, take place 

 when there is no possibility of any consumption of carbo- 

 hydrates or production of CO 2 . 



The fact, however, that the excitatory after-effects de- 

 scribed, disappear on the death of the tissue, has led Dr. 

 Waller to put forward the generalisation that this so-called 

 'blaze-current' is the final distinction between living and 

 non-living matter. His formula, with regard to this, is, * If 

 the object of examination exhibits blaze in one or in both 

 directions, it is living.' He admits, nevertheless, that a sub- 

 stance which is undoubtedly living will not always exhibit 

 the ' blaze-current.' But it is contended that the occurrence 

 of ' blaze ' is an undoubted ' sign of life,' and that thus 

 a strong distinction is to be made between vitalistic and 

 non-vitalistic, or physical, reactions. Hence, as there is 

 supposed to be no excitatory reaction possible in non-living 

 or inorganic matter, it would follow that electrical shocks 

 passed through such a substance, in either direction, should 

 give rise only to those counter-polarisation currents which 

 are known to physicists. In such cases, on reversing the 

 direction of the shock, the direction of the after-current 

 is also reversed ; but in the living substance, it is maintained, 

 the case is quite different. If the direction of the shock be 

 here reversed, the after-current will still appear, with direction 

 unchanged, because in this latter instance it is not generated 

 by the shock, but is, on the contrary, an inexplicable function 

 of the living material, set in action by it, in the same way as 

 a loaded gun is fired by pulling the trigger. The possibility 

 of obtaining from the given substance such a uni-directioned 

 after- current, independently of the direction of the shock, is 

 thus to be taken as the test and token of ' vitality.' 



Now, while it is certainly true that. the domain of physio- 

 logical phenomena has not yet been so thoroughly explored 

 as that of the physical, it is nevertheless equally true that 

 no one could venture to claim that even physical phenomena 



