430 Mr. W. L. Symes and Dr. V. H. Veley. [Dec. 10, 
In such cases,’ when blockage is at all recognisable (fig. 4), abrupt 
irregularity replaces the abrupt regularity of figs. 2 and 3. In fig: 2, 
none of the steps is followed by any recovery during the drug bath, which, 
though slowly acting, is sufficiently concentrated to block with certainty. 
In fig. 3 the last three steps contain examples of reversion to the 
amplitude of the preceding ; the concentration of the solution is just sufficient 
to ensure blockage. In fig. 4 not even the downward trend of the twitches is 
maintained. Here, after initial abrupt diminutions in the muscular response, 
only one stimulus (about 7 minutes after application of the drug) proved 
altogether ineffective, the succeeding stimuli evoking responses tending in 
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Fic. 4.—Failure to Produce Complete Block. 
1. Application of drug, N/300 (= 0:1 per cent.) solution of cocaine base. 
general towards the normal amplitude (cf Wedenski, loc. cit.), though 
interspersed with reversions towards failure. 
In short, even with the weakest solutions that are at all effective, ¢.e. with 
those most favourable to partial blockage of individual nerve fibres, there 
is, as judged by the muscle, no state of stable equilibrium between complete 
blockage of the fibre, on the one hand, and complete conductivity on the 
other. 
These records recall observations by Griitzner,* and by Gotch,t+ that 
stimulation of less than all the motor nerve fibres to a muscle leads to 
submaximal contraction, when similar stimulation of all of them produces 
* Griitzner, ‘ Arch. f. d. ges. Physiol., Bonn,’ 1881, vol. 41, p. 256. 
t+ Gotch, ‘J. Physiol., Cambridge,’ 1902, vol. 28, p. 395. 
