VI. 



1. Introduction. 



I THINK it is now time to break the silence which I have hitherto 

 maintained regarding certain experiments on animal electricity 

 with which I have been occupied for nearly forty years, and to 

 which I attach great importance. I should have been glad to 

 complete this research as far as I was able before publishing the 

 results, but recently electro-physiologists have approached from 

 several sides the province in which I was for so long the only 

 worker, so that by holding back any longer I incur the danger of 

 forfeiting my share of the fruit of a work, respecting which I have 

 more than quadrupled the nonum prematur in annum. I shall there- 

 fore now state the chief views at which I have arrived. In future 

 papers I shall develop more fully what I have said here. 



Long ago I divided the electromotive phenomena of muscle and 

 nerve into three classes *. The first are perceptible without the co- 

 operation of an extraneous current in a condition of rest or action. To 

 these belongs the current of muscle or nerve at rest as well as its 

 negative variation, the case in which the latter is induced electrically 

 being included in so far as the tetanising current is replaceable by 

 any other excitation. If we wish to extend the classification to 

 electrical organs, we must also include in the same class the weak 

 electromotive effects observed in them when at rest, which I call 

 ' the organ current 2 ,' and the shock of the organ in whatever way 

 induced. 



In the second class I placed the extra polar electrotonic currents 

 which appear in nerves during the continuance of an extraneous 

 current and to which there exists nothing analogous in muscle or 

 in electrical organs 3 . 



1 Untersuchungen liber thierische Elektricitat, vol. ii. part ii. p. 377. 



2 Dr. Carl Sachs' Untersuchungen am Zitteraal, Gymnotus electricus, nach 

 seinem Tode bearbeitet von E. du Bois-Keymond, Leipzig, 1881, p. 171 ff. 



3 Eckhard experimented on the organ of the 'Torpedo,' Sachs on that of the 

 electrical eel, in order to obtain electromotive action of the electrical organs by a 



M 2 



