20 



PROFESSOR C. R. MARSHALL ON THE 



The action on the fore limbs of a cat is shown in the uppermost tracings (L) 

 of figs. 1 and 2. Both figures are taken from the same experiment. Previous to 

 the injection shown in fig. 1 an injection of half the dose of tetra-methyl-ammonium 

 chloride had been given. The first figure shows the results of intermittent stimula- 

 tion of the musculo-cutaneous nerve with the secondary coil at 40 cm., the primary 



L 

 R 



H 



b 

 t 



Fig. 2. — Effect of tetra methyl-ammonium chloride on contraction of fore limb produced by continuous stimulation 

 of musculo-cutaneous nerve. Same animal as fig. 1. Letters as in previous figure, x J. 



current being obtained from an accumulator with an B.M.F. of two volts. The 

 wavy appearance of the earlier part of the tracing is due to the presence of small 

 spontaneous rhythmical contractions of the limb. Almost immediately after the cessa- 

 tion of the injection these spontaneous movements ceased and stimulation of the nerve 

 a few seconds later produced a scarcely appreciable effect. In this case total paralysis 

 to this strength of stimulus lasted six minutes, then recovery gradually occurred ; but 

 the nerve did not regain its former irritability, and the stimulus was consequently 

 increased. 



