TESTING IN VACUO 107 



" I have been asked," he said, " why I chose to designate 

 the effects by the name of ' blaze-currents ' rather than 



* positive polarisation currents," or ' post-anodic action 

 currents/ I think you will readily understand the answer 

 to the negative parts of this question. Apart from the fact 

 that the name ' positive polarisation/ . . . has been 

 adversely criticised by Hermann and Hering — shown by 

 them, indeed, to be a misnomer, inasmuch as the effects to 

 which it was applied are demonstrably due to post-anodic 

 action current — I think it is sufficient to refer to the equivocal 

 or antidrome blaze as forbidding the use of the term, 



* positive polarisation/ The use of the term ' post-anodic 

 action currents ' you have just seen to be altogether un- 

 justified for these skin currents ; in one case the current 

 is not post-anodic at all, and in the other it is post-anodic, 

 but of opposite electrical sign to that of a post-anodic state. 

 In muscle and in nerve a post-anodic spot is galvanometri- 

 cally negative ; in the skin it is galvanometrically positive. 

 So that both these cumbersome expressions are happily 

 inapplicable, and a new term is required. I have been led 

 to adopt the term ' blaze-current ' and I think you may 

 now understand how it arose in the study of retinal effects, 

 and how it serves to clearly earmark a natural group of 

 phenomena of a very definite physiological meaning. 



" A ' blaze-current ' is literally and strictly a ' current of 

 action,' but it is a particular kind of action current, and 

 requires a distinctive name. The known phenomenon to 

 which it bears most resemblance is the discharge of an 

 electrical organ, and we shall not infrequently find the 

 term ' discharge,' a convenient indicative word. But as a 

 distinctive and specific name, the word * discharge ' is 

 insufficient, all the more so from the inconvenience that 

 would arise when we have to refer to the ' blaze-currents ' 

 aroused by the condenser discharge. 



" I have had another reason in my mind that has helped 

 to make me use the expression, ' blaze-current.' The great 

 mass of living things, whatever else they may give and take 

 from their surroundings, take oxygen and give carbonic 

 acid ; they may live slowly or they may live quickly — 



