450 HODGE. [VoL. IX. 
apparatus employed can best be understood in connection 
with a typical experiment. 
A pair of spinal or sympathetic ganglia is quickly excised 
from a freshly pithed frog. Each of these is placed immedi- 
ately in a drop of normal solution on a “stage-electrode”’ of 
the following construction (Fig. 1): A plate of thin, clear 
glass (A) of shape indicated in figure and of a size to be con- 
veniently clipped to stage of a Zeiss microscope stand, larger 
size, has two grooves cut in its under surface from margin to 
near centre. These are made deep enough to conceal two fine 
Fic. 1.— MicroscopE STAGE ELECTRODE. 
. Glass plate. 
. Two platinum wires laid in grooves on under side of 
plate and rising through plate to be exposed on 
upper surface to serve as stimulating tips at (C). 
. Exposed portion of electrodes. 
. Platinum wires to support cover-slip. 
. Wires to induction coil. 
. Trough ground in glass plate to carry off stream of 
normal solution. 
Bh 
aheso 
platinum wires, which are cemented in them (4). A half cm. 
beyond central end of grooves the platinum wires are brought 
to upper surface of glass through two needle holes about two 
mm. apart. The ends of the wires are then bent down into 
needle-hole pits in the upper surface of the plate about two 
mm. beyond the first perforations. Shallow grooves in the 
upper surface are made to connect the holes of each pair, so 
that the platinum wires come to lie half exposed on the upper 
surface of plate for a distance of two millimeters (C). They 
are then filed off level with surface of glass. This portion of 
