KATHODIC POLARISATION OF MUSCLE. 341 



hood of the c physiological kathode' and c anode' respectively, 

 and that these experiments give no information as to the pos- 

 sible extension of the changes beyond the place of their direct 

 origin. 



As far as my experiments hitherto go, it seems however that 

 a propagation of the excitatory inhibition does not take place to 

 any great extent in the circumstances under consideration, either 

 from the anode (on closing) or from the kathode (on opening) 

 the exciting current ; the possibility of such a propagation is 

 nevertheless not to be denied, for instances in favour of it actually 

 exist. (Compare my observations on the muscle of the snail's 

 heart.) 



The relaxation of the kathodic end of the muscle, which occurs 

 simultaneously with the opening of the excitation current, explains 

 also the above-mentioned inhibitory after-effect of the electrical exci- 

 tation of the muscle when not fixed in the middle, in case the opening 

 excitation at the anode is inconsiderable. For it is obvious that 

 the nature of the variation in form of the whole muscle at the 

 opening of the current is conditioned solely by the mutual relations 

 of the two antagonistic variations at the poles. If the kathodic 

 opening inhibition preponderates, as is the rule when a muscle 

 is much shortened, then a rapid further elongation must result 

 on opening the current, and this constitutes apparently an after- 

 effect of the anodic closing inhibition, which is usually more 

 marked. 



It follows hence directly, that a complete knowledge of the 

 way in which the above-described mechanical results of excitation 

 of persistently shortened muscle are in conformity with law, can 

 only be gained with the help of the double myograph, and by 

 using the artifice of fixing the muscle in the middle. 



I do not, I think, go too far in regarding the variations of form 

 of a sartorius thrown artificially into a ' tonus-like ' condition 

 by veratrine, as a complete counterpart of phenomena which I 

 discussed as resulting from electrical excitation of the systolically 

 contracted cardiac muscle. Here as well as there, besides the 

 usual polar phenomena of excitation, which certainly appear less 

 clearly than during the condition of rest and under some circum- 

 stances are suppressed altogether, polar processes of inhibition may 

 be also directly demonstrated ; these manifest themselves by the 

 cessation or the diminution of an already existing condition of 

 excitation and a relaxation of the muscle conditioned thereby, 



