KATHODIC POLARISATION OF MUSCLE. 



353 



The deflections, which I observed in the most favourable case under 

 these circumstances, never amounted to more than a few (at most 

 five) scale divisions ; still there could hardly be any mistake about it, 

 as all sources of error were excluded, and it only remained to make 

 the feeble effects more clearly perceptible, by using an instrument 

 so delicate as to make a more exact investigation possible. 



I will give first of all some values of positive kathodic polarisation 

 observed in a fresh, not poisoned sartorius of R. temporaries, when the 

 Edelmann galvanometer was used, in order to compare them with 

 the earlier experiments on veratrine muscle. 



3. Arrangement of experiments as in I and 2. 



In all the experiments which will be described in the following 

 paragraphs, I used a mirror galvanometer constructed by Meyer of 

 Zurich after Hermann's specifications, and which left nothing to be 

 desired as regards sensitiveness. I refer for a description of it to 

 Hermann's paper in Pfliiger's Arehiv l and will only remark that 

 the new instrument used by me has 1000 turns more than that of 

 Hermann. The current from the longitudinal to the transverse 

 section of the sciatic nerve of a medium-sized frog with its lower 

 end lying on the brush electrodes, produced on an average, a 

 deflection of 120-150 scale divisions when the instrument was 

 made aperiodic by Hauy's bar magnet, the leading-off electrodes 

 being about i cm. apart and the distance of the scale from the 

 mirror about 2-5 metres. The demarcation current of the sartorius, 

 when similarly led off, naturally drove the scale at once far out of 

 the field ; consequently whenever there were any considerable differ- 

 ences of tension at the beginning of the experiments of excitation, 

 it was necessary to adjust the compensator approximately before 

 closing the galvanometer circuit. 



1 Pfliiger's ' Arehiv,' vol. xxi. 



A a 



