

PRODUCED BY A CONSTANT CURRENT. 35 



previous size. When the experiment is repeated they finally dis- 

 appear. At the same time the contractions are not instantaneously 

 annulled, but during the first moments after closure of the current 

 small contractions still show themselves, disappearing with continu- 

 ance of the current. 



c. E = 41 ; Rh. = 100. With the same strength of polarising 

 current as in 6 the diminution of the contractions is far less, the 

 distance of the spot stimulated from the pole being greater. 



d. E = 40 ; Rh. = 270. An increased strength of current, on the 

 other hand, makes the contractions at once disappear at a spot lying 

 only i mm. nearer the pole. 



& E 42 ; Rh. = 270. This is also the case 2 mm. higher up. 

 After a little small contractions show themselves for a time, the 

 current remaining closed. 



8. The intrapolar changes of excitability at the negative pole 

 of a descending current. 



The excitability was raised with every strength of current tried, 

 i. e. up to 10 Meidinger's elements inclusive. This rise instantan- 

 eously assumes its full amount when the current is closed. An 

 intensity of the test-stimulus, which shortly before evoked quite 

 small contractions or none, now produces quite strong ones. This 

 increased excitability continues the whole time the current is 

 closed. Yet it is to be observed that the contractions gradually 

 decline during closure of the current, especially with nerves on 

 which repeated experiments have been performed with reference to 

 this point. This decrease, however, is in most cases exceedingly 

 slight, and often does not appear at all. When the current is opened 

 the contractions fall to their original height ; when weak currents 

 were opened no diminution of excitability presented itself in the 

 circumstances under which I carried on my experiments. On 

 the other hand, in the first moments after a stronger current is 

 opened, an evident diminution of excitability is exhibited. To this 

 in many cases succeeds a rise of excitability, which is yet never of 

 consequence and often scarcely recognisable. The increase of ex- 

 citability during closure of the current is greatest at the negative 

 pole. It rises along with the strength of the current up to a 

 certain limit. 



If the experiment is frequently repeated, the increase of the 

 contractions remains about the same during each closure of the 



