144 



Scientific Proceedings (119). 



In the year 1913 the author attempted to solve this question in 

 the physiological laboratory of the University of Giessen under 

 Professor Garten. 



To establish the current of injury a frog's sartorius muscle 

 was cut by a rifle bullet. This bullet cut a copper wire just 

 before entering the muscle substance. The copper wire was 

 shunted across a string galvanometer through which a constant 

 current was passing. This galvonometer immediately responded 

 with an excursion which was used as time marker. After passing 

 the muscle the bullet cut another copper wire shunted across a 

 second galvanometer. This galvanometer was connected to one 

 electrode at the end of the muscle farthest from the injured 

 portion. The other electrode lay beneath the injured portion of 

 the muscle. It was possible to cut all but a few fibers of the 

 muscle by means of the bullet and keep the muscle firmly attached 

 to the electrodes. The moment the rifle trigger was pulled a 

 hymographion carrying film was shot at the speed of 4,000 mms. 

 per second. The galvanometer excursions were recorded on this. 

 It was possible to get uniform velocity over a large portion of 

 the film. A time marker recorded the time and ordinates were 

 established as well as abscissae by mechanical devises. After re- 

 cording a current of injury the two copper wires were replaced and 

 a bullet shot through them as before. In this experiment a 

 constant current equal to the previously measured demarcation 

 current was thrown through the galvanometer at the moment the 

 second copper wire was cut. We thus had a picture of the excur- 

 sion of the string under the influence of a constant current to 

 compare with our demarcation current. It was possible to meas- 

 ure time with an error of less than 1/10,000 of a second because of 

 the speed of the film and the uniformity of the velocity of the 

 hymographion. Apparently all the demarcation current excur- 

 sions of the string reproduced the constant current excursions 

 within the limits of errors of the method. That is the curves 

 covered one another so closely that one could infer that the 

 demarcation current is established with its maximum value within 

 1/10,000 of a second after injury. The strongest objection to 

 the ion theory of the demarcation current is therefore removed. 



