SCIENTIFIC PROCEEDINGS 



Abstracts of Communications. 

 One hundred twenty-ninth meeting. 



Presbyterian Hospital, Neiv York City, February 21, 1923. 

 President Wallace in the chair. 

 113 (2073) 

 Studies on fatigue of voluntary muscles. 

 By LEON ASHER. 

 [From the University of Berne, Berne, Switzerland.] 



A new method was worked out to stimulate the nerve of a 

 voluntary muscle of a mammalian animal, this being kept in a 

 physiological condition without impairing circulation, respira- 

 tion, etc. As no operation was performed the same animal 

 could be used for repeated experiments. Rhythm and strength 

 of tetanic stimuli were controlled. 



In the beginning there occurred a slight drop of contraction 

 height, the "initial fatigue." Then a certain level was reached 

 and maintained for several hours. Fatigue did not ensue if the 

 rhythm of tetanic stimuli was every second second, even every 

 second. The ratio of "excitation period" to "pause period" 

 had a marked influence. In isometric contractions non-fatigue 

 was still more definite than in isotonic contractions. Extirpa- 

 tion of the sympathetic nerve supply on one side had no in- 

 fluence. 



In the frog, fatigue soon ensued when stimulation was made 

 with tetanic stimuli, but break-shocks of an interval down to 

 every fourth second applied with the new method produced no 



