194 JELLY-FISH, STAR-FISH, AND SEA-URCHINS. 
seconds, and continues for a variable number of 
seconds. It generally begins with powerful con- 
tractions, of a less shivering character than those 
which are produced by acids, and therefore still 
more closely resembling the normal swimming 
motions of the unmutilated animal. Sometimes, 
however, the first manifestation of the artificial 
rhythm is in the form of a few gentle rhythmic 
contractions, to be followed by a few seconds of 
quiescence, and then by the commencement of the 
sustained bout of strong contractions. In either 
case, when the bout of strong contractions sets in, 
the rate of the rhythm becomes progressively and 
rapidly increased, until it runs up into incipient 
tetanus. The rate of the rhythm still quickening, 
the tetanus rapidly becomes more and more pro- 
nounced, till at last the bell becomes quiescent in 
tonic spasm.* 
If the bell is still left in the glycerine solution 
nothing further happens; the tissues die in this 
condition of strong systole. But if the bell be 
transferred to normal sea-water immediately after, 
or, still better, slightly before the tonic spasm has 
become complete, an interesting series of pheno- 
mena is presented. The spasm persists for a long 
* Sometimes, however, the order of events is slightly different, 
the advent of the spasm being more sudden, and followed by a 
mitigation of its severity, the bell then exhibiting what is more 
usually the first phase of the series, namely, the occurrence of 
the locomotor-like contractions. Occasionally, also, rhythmical 
shivering contractions may be seen superimposed on the general 
tonic contraction, either in a part or over the whole of the con- 
tractile tissues. 
