KATHODIC POLARISATION OF MUSCLE. 345 



with the description given there 1 . However, I was able here, as 

 well as in the polarisation experiments on muscle of Anodonta, 

 to dispense" with the use of the pendulum rheotome, because the 

 closing time of the exciting current must not be allowed to sink 

 below a limit attainable with the aid of a double switch, if the 

 effects to be described are to come out with sufficient clearness. 

 A more exact determination of the transmission time in each case 

 is of no importance in the experiments now under consideration. 

 Battery currents were used exclusively for excitation, and as a rule 

 I employed two Daniells as the source of current. 



I have already shown in an earlier communication 2 , that by the 

 direct action of properly dilute solutions of acetate of veratrine 

 in 0-6% solution of common salt, it is easy to induce a locally 

 limited condition of the muscular substance, which is identical 

 with that observed in the muscles in their totality when the 

 whole animal is poisoned, and this behaviour serves to make the 

 law of polar excitation by the electrical current directly evident. 

 I also called attention later 3 to the sometimes extraordinarily strong 

 'action current' which may be observed after momentary excitation 

 at any point of a muscle which has been partially treated with 

 veratrine, when the leading off electrodes are applied to the 

 poisoned end of the muscle and to some point of the longitudinal 

 surface higher up. The difference of tension to which this is 

 due is, as I then found, very persistent, and under any circum- 

 stances lasts longer than the visible local persistent contraction of 

 the muscle. 



For the present object, which is solely concerned with the 

 investigation of galvanic changes occurring under the influence 

 of an electrical current in a length of muscle alternately in repose 

 and excited, it was therefore an essential preliminary condition to 

 make the negativity of the latter last as long as possible as an 

 expression of excitation, in order to be able to carry out at least 

 one polarisation experiment during this time. For this purpose 

 a special method of local poisoning is required, and as such, I 

 recommend the following mode, which hardly ever fails if the 

 preparation is of sufficient sensitiveness. 



As in the experiments described in paragraph 2, I used here 

 also almost always the sartorius of R. temporaria, and as a rule I 

 first poisoned the animals with a strong, quickly-acting dose of 



1 Sitzungsber. vol. Ixxxviii. 2 Loc. cit. vol. Ixxx. 



3 Sitzungsber. vol. Ixxxi. p. 107 (Biedermann). 



