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PRACTICAL PHYSIOLOGY 



produces a full contraction (all or none), (2) dur- 

 ing both the period of latency and the progress of 

 the contraction produced by one excitation the 

 muscle gives no response to a second excitation; 

 in other words, there is a prolonged refractory 

 period, (3) no superposition is produced by succes- 

 sive stimuli, and therefore no true tetanus, (4) after 



