500 PROFESSOR C. R. MARSHALL ON THE 



seconds later. As is seen, the contracture produced is well marked. Continued 

 stimulation of the nerve during the contracture, however, produced relatively little 

 effect. If the tetra-methyl-ammonium chloride solution is applied during the 

 stimulation of the nerve, a much smaller effect is obtained, owing probably 

 to the greater difficulty of penetrating the muscle. And the effect is still less 

 marked if the solution be applied during continuous stimulation of the muscle 

 directly. 



After paralysis of the nerve-endings with small concentrations of tetra-methyl- 

 ammonium chloride, the substitution of Ringer's fluid within two or three minutes 

 of the paralysis caused recovery to commence a few minutes later. A considerable 

 degree of recovery was early reached, but complete recovery was not obtained until 

 the preparation had remained for an hour or more in the Ringer's solution. With 



Fig. 12. — Eti'ect of 0'4 per cent, tetra-methyl-ammonium chloride on gastrocnemius 

 after long-continued stimulation of sciatic nerve (see text). The arrow indicates 

 time of application of the solution ; the thick white lines the time and duration 

 of stimulation of the nerve with secondary coil full up. Time in ten seconds. 



solutions approaching isotonic in strength, the recovery obtained from the paralysis 

 of the nerve-endings was very incomplete ; that from paralysis of the contractile 

 tissue of the muscle was rapid and complete. The latter is seen in fig. 13, which 

 also shows the absence of contracture after the previous application of another 

 quaternary compound. The muscle was first treated with 1'4 per cent, di-methyl-di- 

 ethyl-ammonium chloride, with the result shown in fig. 16, and the action was 

 allowed to continue for two and a half hours, at the end of which time slight 

 contractions were still obtained with the secondary coil full up. The solution 

 was then replaced by Ringer's fluid and the muscle allowed to remain unstimulated 

 in it for two hours. Afterwards 1*69 per cent, tetra-ethyl-ammonium chloride 

 was applied for ten minutes and replaced in turn by Ringer's solution. The 

 isotonic solution of tetra-methyl-ammonium chloride was introduced twenty-two 

 minutes later. 



Tri-methyl-etJiyl-ammonium Chloride. — The action of tri-methyl-ethyl-ammonium 

 chloride on the nerve-endings and muscle was found to be similar to but weaker 

 than that of tetra-methyl-ammonium chloride. No contracture was obtained in 



