OF THE GALVANIC CURRENT ON THE MOTOR NERVES OF MAN. 967 
The poles of a galvanic battery (PA) are connected with tbe commutator (Cj), 
provided with its cross wires; a commutator (Co), without its cross wires being 
inserted between the battery and its commutator (C^), and serving to direct the 
current from the secondary coil (S.c.) through the battery or through the resistance 
(Pj) oot less than that of the battery.* The secondary coil (S.c.) is connected with 
the commutator (C 2 ). To the outer holes of the commutators (C lf C 2 ) are connected 
the two electrodes (E, E). The inner holes of (C 1} C 2 ) are connected through a 
galvanometer (G) and a resistance (P 3 ). 
Either current can thus be reversed independently of the other by the commutators 
Cj, C 2 , and the movable electrode can be made at will kathode or anode of the make 
or break induction current, with or without kathode or anode of the galvanic current. 
The combinations possible are :— 
Anode of the break induction current with Anode of the galvanic current. 
Kathode „ „ „ Kathode „ „ 
Anode ,, „ „ Kathode „ 
Kathode „ „ „ Anode „ „ 
Anode of the make induction current with Anode of the galvanic current. 
Kathode „ „ „ Kathode „ „ 
Anode „ ,, ,, Kathode „ }} 
Kathode „ „ „ Anode „ 
These are schematically represented in the following diagram,— III. A. representing 
the conditions of make excitation. III. B. those of break excitation. 
* We found, however, that this precaution may be safely dispensed with, the battery used being of 
low internal resistance. 
6 H 
MDCCOLXXXII. 
