PHARMACOLOGICAL ACTION OF TETRA-ALKYL-AMMONITTM COMPOUNDS. 503 



contracture, followed by rapid diminution in the height of the contractions. A small 

 terminal irritability to this strength of stimulus continued for some time as before, 

 and slight contractions were still obtained with the secondary coil full up two and 

 a half hours after the immersion. 



Influence of 1 '4 per cent, di-methyl-di-ethyl-ammonium chloride on the irritability of the sartorius of the frog. Secondary coil at 12 cm. Later it was 

 placed at 6 cm., and a second series of contractions taken. Arrow indicates time of applying drug. Contractions x 5. Time in ten seconds. 



The terminal irritability of the nerve to continued faradic stimulation is shown 

 in fig. 17, which is a continuation of the experiment illustrated in fig. 15, and is 

 given as being typical of the terminal effects obtained with the other substances. 



Fio. 17. — Continuation of fig. 15, showing terminal irritability of nerve. C indicates position of secondary coil. N refers 

 to nerve, and M to muscle. The thick lines give the duration of the stimulation. Time in ten seconds. x§. 



The interval between the two tracings was four and three-quarter minutes, and 

 during this time the nerve was stimulated with the secondary coil full up for two 

 minutes with similar results, except more powerful contractions and less marked 

 exhaustion, to the first stimulation shown. The effect of stimulating the muscle 

 directly with the secondary coil at 12 cm. and full up is also seen. In most cases the 



