ANIMAL ELECTRICITY. LECTURE IV. 83 



It is not my present purpose to enter into any- 

 detailed examination of this law of response ; that 

 will form part of a future course of lectures. But it 

 is necessary, in order to make clear to you the relation 

 between the excitability and the electro-mobility of 

 living- matter, that I should allude to them now, if 

 only to warn you that "excitability" and "electro- 

 mobility " are not parallel attributes — that the term 

 excitability is, in English, subject to an ambiguity 

 that is avoided in the richer German by the terms 

 Erregbarkeit and Leistungsfahigkeit, and that one 

 of the several reasons leading me to adopt " zinc " as 

 a new root word has been that its substantive "zinc- 

 ability " {i.e., capability of being aroused to action 

 analogous with that of the zinc of a voltaic couple) 

 does not naturally lie wide open to ambiguity, as do 

 the terms excitability and electromobility. By the 

 terms "greater excitability," "more excitable," there 

 may be implied "more easily excited," or "capable of 

 greater reaction." By the terms " greater electromo- 

 bility," "more electromobile " might be implied "more 

 easily aroused to electromotive action," or capable 

 of beine aroused to oreater electromotive action. 



By the terms "greater zincability," "more zinc- 

 able " it is most natural to understand — and at any 

 rate it is the sense in which the expression will be 

 used in these lectures — capability of being aroused to 

 greater electromotive action, analogous with that of 

 the zinc in a voltaic couple. That is the sense in 



