PHARMACOLOGICAL ACTION OF TETRA-ALKYL-AMMONIUM COMPOUNDS. 505 



were paralysed in twenty-one minutes, the muscle at this time showing considerable 

 irritability to direct stimulation. Two minutes later the nerve and muscle were 

 subjected to continued stimulation with the secondary coil full up, with the result 

 shown in fig. 20. Afterwards the isotonic solution of tetra-ethyl-ammonium chloride 



Fig. 20. — Continuation of previous figure, showing terminal irritability of nerve. 

 N= stimulation of nerve with coil full up. M = stimulation of muscle. 

 Time in ten seconds. 



was replaced by Ringer's fluid, and left until next day. The nerve was then 

 unheritable, but the muscle contracted with the secondary coil at 12 cm. 



Ammonium Chloride. — Although the paralysing influence of ammonium chloride 

 on the nerve-endings has long been known, it seemed desirable to add a comparative 



Fig. 21. — Effect of isotonic solution of ammonium chloride on irritability of gastrocnemius of frog. Description as in 

 fig. 14. An interval of seventeen minutes occurred between the two parts of the tracing. 



experiment with this substance carried out under similar conditions to those described. 



The result is shown in fig. 21. The nerve-endings were paralysed in twenty -five 



minutes, the muscle having lost relatively little irritability. Continued stimulation 



of the nerve and muscle was commenced one and a half minutes later, and gave 



similar results to those obtained with the alkyl-ammonium compounds (fig. 22). 



These experiments on the isolated nerve-muscle preparation also show, like those 

 TRANS ROY. SOC. EDIN., VOL. L. PART II. (NO. 17). 72 



