ARTIFICIAL RHYTHM. 197 
artificial rhythm. Consequently, whether the 
specimens experimented upon be entire or paralyzed 
by removal of their margins, the phenomena of 
artificial rhythm under the influence of chemical 
stimulation are the same. But although the spon- 
taneity of the ganglia disappears before the artificial 
rhythm sets in, such is not the case with the reflex 
activity of the ganglia; for on nipping a tentacle of 
the quiescent bell before the artificial rhythm has 
set in, the bell will give a single normal response to 
the stimulation. 
Hence, in historical order, on dropping an unmuti- 
lated specimen of Sarsia into a solution of glycerine 
of the strength named, the usual succession of events 
to be observed is as follows. First, increased 
activity of the normal swimming motions, to be 
quickly followed by a rapid and progressive decrease 
of such activity, till in about fifteen seconds after 
the immersicn total quiescence supervenes. “Four 
or five seconds later the manubrium begins to re- 
tract by rhythmical twitches, the rate of this 
rhythm rapidly increasing until it ends in tonic 
contraction. When the manubrium has just become 
fully retracted—or very often a little earlier—the 
bell suddenly begins its forcible and well-pro- 
nounced rhythmic contractions, which rapidly in- 
crease in their rate of rhythm until they coalesce 
into a vigorous and persistent spasm. If the animal 
be now restored to normal sea-water, spontaneity 
will return in a feeble manner; but there is always 
afterwards a great tendency displayed by the bell 
to exhibit shivering spasms instead of normal 
