PHARMACOLOGICAL ACTION OF TETRA-ALKYL- AMMONIUM COMPOUNDS. 501 



sartorii not previously immersed in a normal saline solution, and the behaviour after 

 previous immersion in calcium chloride solutions was the same as that already 

 described. The influence of an isotonic solution on the irritability of the gastro- 

 cnemius muscle to direct and indirect stimulation is seen in fig. 14. This and the 



Fig. 13. — Influence of 1*12 per cent, tetra-methyl-ammonium chloride on the irritability of the sartorius to direct stimulation. 

 1*4 percent, di-methyl-di-ethyl-ammonium chloride and 1'69 per cent, tetra-ethyl-ammonium chloride had been previously 

 applied. For description see text. The first arrow shows the time of application of the tetra-methyl-ammonium chloride 

 solution ; the inverted arrow the time of its removal ; the arrow marked R the time when Ringer's solution was added. 

 The stimulations were made with the secondary coil full up. Time in ten seconds, x §. 



other figures of a similar character were carried out within a short time of one 

 another on the same batch of frogs and under the same conditions. Stimulation 

 of the nerve by break shocks with the secondary coil at 48 cm., and of the 

 muscle by break shocks with the secondary coil at 34 cm., produced a good 

 contraction in each case, except the experiment in which ammonium chloride was 



Fig. 14. — Effect of 1*27 percent, tri-methyl-ethyl-ammonium chloride on irritability of gastrocnemius to direct and indirect 

 stimulation. Secondary coil at 12 cm. Each direct is followed by an indirect stimulation. The arrow indicates the 

 time of application of the solution. The preceding contractions were taken in Ringer's solution. Weight 5 g. Time in 

 ten seconds. 



used. The position of the secondary coil required to give a good contraction of the 

 muscle in' this case was, for the nerve, 44 cm., for the muscle, 30 cm. The primary 

 current was obtained from an accumulator cell giving an E.M.F. of two volts. 

 The subsequent stimulations of nerve and muscle were made with the secondary 

 coil at 12 cm. ; and the stimulation, first of muscle and then of nerve, was repeated 

 every ten seconds, with an interval every minute. A normal series of contractions 

 with the muscle immersed in Ringer's solution was taken, and, after the substitution 



