386 Dr. C. B. Radcliffe's Researches in Animal Electricity. [Apr. 8, 



is more intelligible than any which can be found in the action of the 

 currents themselves, and that in fact it is a gain rather than a loss to 

 discard altogether the " inverse " and " direct " currents from the field 

 of operation in which they have hitherto been supposed to play so all- 

 important a part. 



It would seem, in fact, that the evidence in this section agrees with 

 that supplied in the two previous sections in leading to the conclusion 

 that muscular relaxation is associated with a state of charge, and mus- 

 cular contraction with a state of discharge. It would even seem as if 

 all the evidence so far gave countenance to the conclusion that the state 

 of charge may cause muscular relaxation by keeping the molecules of the 

 muscle in a condition of mutual repulsion, and that the state of discharge 

 may lead to muscular contraction by doing away with that state of elec- 

 trical tension which prevents the molecules of the muscle from yielding to 

 the attractive force, inherent in their physical constitution, which is ever 

 striving to bring them together. 



V. On Electrotonus. 



It is not enough to be content with repeating, after Professor Du Bois 

 Reymond, that the nerve-current and voltaic current are in the same direc- 

 tion in anelectrotonus and in opposite directions in cathelectrotonus, or, 

 after Professor Eckhard, that the activity of the nerve is paralyzed in the 

 former of these states and exalted in the latter. In fact, the subject of 

 electrotonus requires complete revision. 



The direction of the nerve-current and voltaic current is found to agree 

 in anelectrotonus and to disagree in cathelectrotonus, if, as is commonly 

 the case, the direction of the former current is from the end to the 

 side of the fibres ; but not so if, as may happen, the course of the 

 nerve-current is the reverse of this. In this case the direction of the two 

 currents will agree in cathelectrotonus and disagree in anelectrotonus. 

 Nay, more, there are movements of the needle, corresponding perfectly to 

 those which happen in the two electrotonic states, when the experiment 

 is made upon dead nerve and upon other bodies too, provided these 

 bodies are sufficiently bad conductors of electricity. 



If a piece of wire be placed as the piece of nerve is placed in an ex- 

 periment on electrotonus and dealt with in the same manner, the needle of 

 the galvanometer remains motionless ; and so likewise if a piece of cotton 

 or hempen thread moistened with water be substituted for the wire ; but 

 not so if the nerve be represented by silk or gutta percha moistened with 

 water. In the latter case, indeed, the needle is found to move as it 

 moves in anelectrotonus and cathelectrotonus when the voltaic poles are 

 placed in the way necessary to produce these two electrotonic conditions. 

 The needle may be at zero before these movements are manifested, or it 

 may not. It is at zero if the electrodes of the galvanometer are homoge- 

 neous ; it is on this or that side of the zero-point if, as commonly happens, 



