ON NEKVE-EXCITATION BY THE NERVE-CUKRENT. 151 



with any satisfactory result. I may mention finally that I have 

 repeatedly obtained secondary tetanus of the muscles supplied by 

 the axillary plexus, by peripheral excitation of the ulnar nerve 

 prepared up to the axilla and divided above the elbow, the axillary 

 plexus having been previously divided. 



It can not be supposed that the above-described secondary effects 

 can be attributed to escape of current or to unipolar excitation. 

 The electrodes fine platinum wires, 2 or at most 3 mm. apart were 

 placed quite close to the transverse section, so that the break induc- 

 tion currents were ascending 1 (abterminal) in the nerve, and the 

 induction coils used with one Daniell were separated by a distance 

 of from 5 to 40 cm. or at most 30 cm. for comparatively less 

 excitable preparations. Such weak induction currents, although 

 acting energetically close to the transverse section, generally lost 

 all effect as soon as I moved the electrodes further away from the 

 transverse section towards the muscles. Whenever this was not 

 the case I did not regard the experiment as completely trustworthy. 

 If I made the induction currents descending (atterminal) in the 

 nerve, I obtained no effect with currents which had acted ener- 

 getically in the opposite direction, so long as the electrodes were 

 very near the transverse section. Effects were produced however, 

 either with the same or with a somewhat increased current strength, 

 as soon as I moved up the electrodes from the end of the nerve 

 at the knee ; generally disappearing again if I brought the elec- 

 trodes still nearer to the muscles. There were however exceptions 

 to this. These facts are sufficient to make the above-named objection 

 inadmissible. But as regards the possibility that my experiments 

 have in them nothing but the paradoxical contraction described by 

 du Bois-Ueymond, I shall presently discuss this matter for the 

 satisfaction of those who may still have doubts. 



I have not confined myself to obtaining secondary tetanus by 

 tetanising the primary nerve with induction currents, but I have 

 also used with the same result weak battery-currents, rendered 

 tetanising by means of a rotating commutator. 



Further, I have obtained strong secondary single contractions 

 in great number by means of single induction shocks and by 

 closure of weak battery-currents. What weak currents suffice for 

 this purpose is shown, for instance, by an experiment in which, 

 with one Daniell and only 4-5 cm. of the double wire of du Bois- 

 Keymond's rheochord as resistance, I obtained a strong secondary 

 contraction at each closure, when I made this weak current 



