V. 



AT the end of my communication 1 on the direct excitation of 

 muscle by the muscle-current, I promised to communicate analogous 

 observations on nerves, and to prove that the excitation of nerves 

 by the nerve-current occurs more frequently and is more easily 

 accomplished than has been hitherto supposed. But in the winter 

 of 1879 the frog-s at my disposal suddenly became unfit for such 

 experiments, and I was obliged to interrupt them. 



Since then Kiihne 2 has communicated observations on the excita- 

 tion of nerve by its own current, which I shall have occasion to 

 confirm in the following pages. My researches, however, in many 

 respects go beyond those of Kiihne, especially in this, that I have 

 succeeded in eliciting from nerves a true secondary contraction 

 and secondary tetanus, which neither du Bois-Reymond nor Kiihne 

 held to be possible, and I have so definitely learned the condi- 

 tions necessary to the success of these experiments, that they will 

 henceforth be easily and successfully repeated by anyone. 



1. Excitation of the Nerve by its own current. 

 Du Bois-Reymond' s Experiment. 



As is well-known, du Bois-Reymond showed that it is possible 

 to excite, by means of its own current, a nerve which is provided 

 with a transverse section. Placing the sciatic, separated from its 

 centre, and in connection with its muscles, so that transverse and 

 longitudinal sections respectively were in contact with the cushions 



1 Sitzungsberichte, Ixxix. 3. p. 7. 



2 Untersuch. aus d. physiol. Inst. zu Heidelberg, iii. p. 90, 1879. 



