CO-ORDINATION. 137 
the natural rhythm) which passed from 8 to A, one 
would pass from A to B.* 
Of course the only interpretation to be put on 
these facts is that every time an artificially started 
wave reached the terminal ganglion it caused the 
latter to discharge; but that the occurrence of a 
discharge could not in this case be rendered ap- . 
parent, because of the inadequacy of that discharge 
to start a reflex wave. But that such discharges 
always took place was manifest, both @ priori be- 
cause from analogy we may be sure that if there 
had happened to be any contractile tissue of appro- 
priate width on the other side of the ganglion, the 
discharge of the latter would have been rendered 
apparent, and @ posteriori because, after the arrival 
of every artificially started wave, the time required 
for the ganglion to originate another wave was pre- 
cisely the same as if it had itself originated the 
previous wave. 
In view of these results, it occurred to me as an 
interesting experiment to try the effect on the 
natural rhythm of exhausting a ganglion thus situ- 
ated, by throwing in a great number of shocks at 
the other end of the strip. I found that after five 
hundred single shocks had been thrown in with a 
rapidity almost sufficient to tetanize the strip, im- 
mediately after the stimulation ceased, the natural 
* When two such waves met, they neutralized each other at 
their line of collision ; or perhaps more correctly, the tissue on 
each side of that line, having just been in contraction, was not 
able again to convey a contraction-wave passing in the oppo- 
site direction to the wave which it had conveyed immediately 
before. 
