246 RESEARCHES ON SECONDARY ELECTROMOTIVE 



moistened with -6 per cent, salt solution, and the two electrodes re- 

 placed in their respective positions. After the strong- descending" 

 * demarcation ' current had become constant, it was compensated, 

 and the muscle was again stimulated for the same peri6d with the 

 same descending current ; on breaking, negative polarisation resulted 

 to the amount of 36 divisions of scale. 



Tn destroying the muscle by heat it is necessary to defer 

 exciting anew until the heated portion cools down. The result 

 is the same if the muscle is locally destroyed by crushing with 

 a pair of pincers. After crushing the lower end of the sartorius, I 

 obtained only slight negative anodic polarisation, with ascending 

 currents of the same strength and duration as those with which I 

 had obtained positive anodic polarisation, amounting to far more 

 than 100 divisions of the scale, from the uninjured lower end of the 

 muscle. And even with the whole current from 2 Daniells and 

 with 10 sees, closing time, I obtained only weak negative polari- 

 sation to the amount of 2O SC , whereas when the lower end of the 

 muscle is in a normal condition, the whole current is wont to give 

 such a strong positive anodic polarisation current, even with short 

 closing time, that the image of the scale shoots out of sight. The 

 difference of action before and after destruction is in this case more 

 prominent, because the current enters the normal lower end of the 

 muscle with greater density than it does the living muscle substance 

 above the crushed end. That the muscle substance lying above the 

 lower destroyed portion, and that lying below the upper destroyed 

 portion as well as the whole remainder of the uninjured muscle, has 

 not lost its susceptibility for positive anodic polarisation, can be 

 easily shown by control experiments. 



The fact thus established, that the stimulating current which 

 passes through dead and dying muscle substance to enter muscle 

 which is still excitable and living, is not in a condition to produce 

 positive anodic polarisation in the anodic spots of the latter, 

 as well as the fact shown in Biedermann's researches that it is 

 incapable of producing the break-contraction, proves that the 

 cause of so-called positive polarisation must be sought for, for the 

 most part if not exclusively, not in changes which the current 

 directly produces in the whole or in some part of the intrapolar tract, 

 but in changes taking place at the anodic spots of the muscle sub- 

 stance, which spread more or less from the latter into the former. 

 The positive polarisation-current is thus dependent upon the integrity 

 of the anodic spots of the excitable substance. 



