PHARMACOLOGICAL ACTION OF TETRA-ALKYL-AMMONIUM COMPOUNDS. 389 



a solution of commercial tetra-ethyl-ammonium chloride of not less than 1 in 1000 

 strength, contracture results, the rapidity and height of the contraction depending on 

 the particular muscle employed, to some extent on the weighting of the muscle, and, 

 within limits, on the concentration of the solution. The contraction is usually 

 followed by some relaxation, and the muscle then passes into rigor. The effect is 

 obtained after curarising the muscle and after paralysing the nerve-endings by 

 gradually increasing concentrations of tetra-methyl-ammonium chloride (fig. l). 

 It is not obtained with any strength of pure tetra-ethyl-ammonium chloride up 

 to slightly hypertonic solutions. By comparing the action of concentrations of 



Fig. 1. — Effect of commercial tetra-ethyl-ammonium chloride on isolated frog's sartorius. The 

 muscle was first immersed in a bath of - 25 per cent, curarin and afterwards in 1 per cent, 

 tetra-methyl-ammonium chloride. The arrow indicates immersion in - 5 per cent, tetra- 

 ethyl-ammonium chloride. Time in minutes. Lever increased contraction five times. 



hydrochloric acid in Ringer's solution of the same acid strength as the solutions of 

 commercial tetra-ethyl-ammonium chloride it was found that a similar action was 

 produced in each case, and consequently the contracture appears to be wholly due to 

 the presence of the acid in the commercial salt. When a muscle was immersed in 

 an isotonic or slightly hypertonic solution of pure tetra-ethyl-ammonium chloride, no 

 effect except very gradual and slight relaxation, such as often occurs in a normal 

 muscle in normal saline solution, followed. Fibrillary tremors were rarely observed, 

 and there was relatively little diminution in the irritability of the muscle substance. 

 The nerve-endings were paralysed, but this action occurred relatively slowly and 

 required twenty minutes or more with an isotonic solution for its development. If 

 early in the intoxication of a nerve-muscle preparation the nerve be stimulated with 

 a faradic current for some time, a curious clonic form of curve is obtained (fig. 2), 

 due to the ordinary nervous disturbances being interrupted by irregular more or less 



