LIVING TORPEDOS IN BERLIN. 459 



be, they serve as the foundation of a considerable advance in the 

 knowledge of this organ. In place of the annoying discrepancy 

 between Sachs' results with Gymnotus and mine with Malapterurus, 

 we see that in all the three electrical fish the secondary electro- 

 motive phenomena of the organ are the same. It has been possible 

 to follow these phenomena more in detail in the Torpedo than in 

 Malapterurus, and still more completely in Gymnotus. The mere 

 fact that the Torpedo organ, instead of being scarcely available for 

 these experiments, turns out to be well adapted to them, is of great 

 value, and in connection with the prospect of having at our disposal 

 in this laboratory living Torpedos, gives reason to hope that what 

 was only roughly sketched out in haste may be more completely 

 investigated. It might perhaps be advisable to postpone till then 

 the discussion of what has been already gained. It cannot do 

 harm, however, to set forth the actual condition of things, and to 

 indicate the chief points of view which have next to be taken. 

 The relatively negative polarisation, equally strong in the two 

 directions, which simply increases up to a certain limit with the 

 density and duration of the current, we will for the present con- 

 sider as ordinary internal polarisation, although as in muscle and 

 nerve its dependence upon vitality and its destruction by a boiling 

 temperature raises some doubt. 



Our newer experience leads us to regard it as much more difficult 

 to form an idea of the nature of the absolutely positive polarisation 

 which is even provisionally satisfactory. There can be no doubt that, 

 in opposition to relatively negative polarisation, it appears as if it 

 were the more physiological process of the two. Its dependence on 

 vitality is greater, it is the first to disappear when the organ dies. 

 There are, however, two different ways of considering it. The first 

 consists in looking upon it along with the organ current as the after- 

 effect of a shock liberated by electrical excitation ; the second in 

 considering it as the consequence of a pile-like arrangement of the 

 electromotive molecules determined immediately by the homo- 

 dromous current. 



At first sight there appear to be strong grounds for accepting the 

 former explanation. As we explain the shock itself by a pile-like 

 arrangement of electromotive molecules, it may be asked how this 

 arrangement may be distinguished from that indirectly generated 

 through the homodromous current (corresponding to absolutely 

 positive polarisation) and why the latter should not always assume 

 the character of a shock. The second interpretation, according to 



