J 42 ANIMAL ELECTRICITY. LECTURE VI. 



But I have thought that the possible confusion 

 of ideas resulting from such experimental complica- 

 tion might overbalance the advantage of the exten- 

 sion of data, and even the distinct practical advantage 

 in certain cases, of being able to ■ test short bits of 

 living tissue through a single pair of electrodes. 



Besides, if the principle has been mastered, its 

 manifold applications can present no further difficulty ; 

 an allusion to them will have been sufficient, their 

 detailed description would be superfluous and there- 

 fore tedious. 



An action-current, however excited, and under 

 whatever circumstances, whether as a negative varia- 

 tion of an injury current, or as a positive variation of a 

 polarising current, or as a negative variation of an elec- 

 trotonic current, is due to a physiological (= physico- 

 chemical) inequality between two points. Active tissue 

 is "zincative," resting tissue is " zincable." 



Look at this last diagram. Is it not forbidding.^ 

 It summarises all the currents experimentally detected 

 in nerve ; I shall not undertake to wade through their 

 redescription in cold blood. To anyone who has not 

 mastered their key, they must remain unintelligible ; 

 to anyone who has mastered their key, they will be a 

 legible and symmetrical page in the story of living 

 matter. 



