INO: 3>] SLOUDY OF “THE NERVE (CELL, 451 
the wires, of course, acts as the electrodes, and the prepara- 
tion is arranged so that either the ganglion lies between the 
electrodes, or its nerve lies ever them. The other end of each 
platinum wire is soldered to an insulated copper wire which 
goes to secondary coil. Two other platinum wires (2) support 
the cover-slip. These, for convenience, are hooked into pits in 
the glass, and are so bent and adjusted as to direct the stream 
of normal solution over the specimen. 
With the plan of this simple electrode understood, the 
remainder of the method may be seen at a glance in Fig. 2. 
Each electrode is clipped to its microscope and a stream of 
normal solution is drawn from flask (1) by means of glass 
syphons (2,2') which end in finely drawn nozzles. These are 
placed at edge of cover-slip opposite trough (7), Fig. 1. The 
stream from (F) drips into beaker (3,3'). Other parts of figure 
need no explanation, 
We now have, living in the same fluid, corresponding gan- 
glia of the same animal. A group of cells, as nearly alike as 
possible, is sought out in each preparation and brought to 
centre of field. A cell, or several cells in each, are measured 
and outlined with aid of camera, and then electrical stimulation 
is applied to one of the preparations, and not to the other. 
Both are watched, and at intervals measured and drawn. Two 
cameras, each attached to its microscope, were used at first 
(as shown in Fig. 2). To render the two pictures more com- 
parable, avoiding thus any difference in the angle of the 
mirrors, a camera was clamped to the eye-piece, with mirror 
firmly set, and eye-piece and camera were lifted together from 
one microscope to the other. 
Stimulation was interrupted, 1§ seconds’ work alternating 
with 45 seconds’ rest, the primary circuit current being made 
and broken by a “ Lombard clock interrupter.” Four Daniel 
cells, supplying current of .2 ampere were used throughout. 
The induction coil used was one of Kruger’s (10305 U.). 
Aside from the electrode and device for supply of normal 
solution the apparatus was made as similar as possible to that 
used in my earlier experiments and fully described in the 
paper just cited. 
