OF THE GALVANIC CURRENT ON THE MOTOR NERVES OF MAN. 
989 
Tracing 25. The upper line shows the latency of three coinciding contractions by 
closure of the galvanic current through both arms. The small vertical line 
marks the instant of excitation. 
The lower line shows the interval between the instant of removal of 
the galvanic current and contraction by excitation by the (physiologically) 
released faradic current, the poles being for the arm explored anode galvanic 
and Jcathode break faradic. Three contractions coincide. 
The middle line shows the same latency with the poles reversed, these 
being for the arm explored kathode galvanic and anode break faradic. 
The closure latency (upper line) is determined in the usual way by a 
catch fixed to the cylinder. The liberation interval (two lower lines) is 
determined by causing a metal surface fixed to the cylinder to short-circuit 
the galvanic current for a given period, thus subtracting it from the combined 
faradic and galvanic circuit. The contractions registered are taken from the 
right forearm. The interruptions of the inducing current are made by a 
reed vibrating 200 per second. A chronograph records 100 vibrations per 
second below the tracing. 
Tracing 26. The two groups are kathodic closure contractions by 10 cells (6 milli- 
webers). 1000 ohms’ resistance in circuit. For the group of contractions to 
the right the closure excitations were made by bridging a break in the 
principal circuit; for the group to the left by breaking a bridge in a 
deriving metallic circuit. 
Tracing 27. The two groups are anodic closure and opening contractions by 30 cells 
(23 milliwebers), 1000 ohms in circuit. For the group to the right the 
closure excitations were made by bridging a break in the principal circuit, 
the opening excitations by breaking a bridge in that circuit; for the group 
to the left the closure excitations were made by breaking a bridge in a 
deriving metallic circuit, the opening excitations by bridging such a break. 
The tracings show that a stronger make excitation is obtained by closing a 
key in the principal circuit than by opening a key in a deriving metallic 
circuit, and that a stronger break excitation is obtained by closing a key in a 
deriving metallic circuit than by opening a key in the principal circuit. 
The effects of excitation made in these two ways must not therefore be 
compared. 
