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PROFESSOR C. R. MARSHALL ON THE 



of the muscle may be present after twenty-four hours' immersion. As previously 

 stated, contracture is not produced by tetra-methyl-ammonium chloride solutions if 

 the muscle has been previously immersed in a solution of some other member of 

 this series ; and contracture may not be produced after the muscle has been 

 subsequently immersed for some time in a normal saline. In this case the irritability 



Fig. 10. — Effect of 1*12 per cent, tetra-methyl-ammonium chloride 'on: gastrocnemius. Upper tracing shows effect on un- 

 stimulated right gastrocnemius ; lower tracing on left gastrocnemius stimulated directly and indirectly. Secondary 

 coil at 12 cm. Both muscles previously immersed in Ringer's fluid. Weight 5 g. Time in ten seconds. 



Fig. 11. — Effect of 0'3 per cent, tetra-methyl-ammonium chloride on irritability of gastrocnemius. Direct, followed by 

 indirect, stimulation every ten seconds. The preparation had lain for twenty and a half hours in Ringer's solution. 

 Small cross indicates interval of one hour. Time in ten seconds. 



of the muscle is influenced by tetra-methyl-ammonium chloride in much the same 

 way as a normal muscle (fig. 13). 



If a gastrocnemius is immersed in an isotonic tetra-methyl-ammonium chloride 

 solution, and the sciatic nerve is regularly stimulated with break induction shocks, 

 the resultant tracing obtained is very similar to that produced when the muscle is 

 stimulated directly. The nerve, however, is more quickly paralysed (fig. 10). 



