ii CHANGE OF FORM IN MUSCLE DURING ACTIVITY 151 



muscles are also exhibited here in regard to duration of 

 expansion, which is greater at the excitation point of the 

 cruralis than in semimembranosus. The rate of transmission per 

 second in the latter is 5417-11,364 mm., in the former 3000- 

 34,000 mm. The value of the red (sluggish) rabbit muscle 

 therefore tallies with the rate of transmission (3500 mm. per 

 sec.) determined by Bernstein and Steiner for the nictitating 

 muscle of the dog. And if comparative observations on the velo- 

 city at which excitation is transmitted in the striated muscles of 

 different animals thus establish a close ratio between the dying- 

 out of the contraction-process at any point and the rapidity of its 

 conduction, the same appears no less clearly from the fact- that in 

 a muscle preparation, where the length of twitch is altered 

 experimentally in a plus or minus sense, the rate of conductivity 

 is equally affected by the same data, e.g. in particular, fatigue 

 (death), and alterations of temperature. 



As in warm-blooded, striated muscles the length of twitch 

 and general excitability diminish more rapidly after any injury 

 than in those that are cold-blooded, so with conductivity only in 

 a much more pronounced degree ; for it is always this property 

 which is the first to suffer, and even to disappear, at a time when 

 local excitability can still be easily demonstrated. The further 

 investigation of these manifestations of decline in warm-blooded 

 muscles presents many points of interest. Since the rate of con- 

 ductivity diminishes constantly, and more rapidly than excitation, 

 we seem to have at hand a simple means of following the wave 

 of contraction with the unaided eye without artificial assistance. 

 Schiff (8) was the first to demonstrate that local mechanical 

 excitation, applied shortly after the death of the animal to an 

 exposed muscle, produces a swelling which remains stationary, 

 while two waves of contraction spread almost at the same moment 

 on either side to both ends of the muscle. " While the contraction 

 is proceeding, the parts adjacent to the now pronounced swelling 

 relax. If the wave of contraction has reached the end of the 

 muscle, it turns back towards its starting-point. But in the mean- 

 time a new wave has started from the point of excitation in both 

 directions, which encounters the reflected wave and crosses it, and 

 this interference repeats itself frequently, because each wave after 

 crossing runs on undisturbed till eventually it grows weaker and 

 dies out." As the muscle becomes more and more moribund, and 



