216 JELLY-FISH, STAR-FISH, AND SEA-URCHINS. 
Sarsiz never respond to a single stimulus with 
more than a single contraction, these multiple 
responses must, I think, be ascribed to a state of 
exalted reflex irritability. After a long exposure 
to the poison, however, only a single response is 
given toeach stimulus; and still later all irritability 
ceases. On now transferring the Sarsiz to un- 
poisoned water, recovery is effected even though 
the previous exposure has been of immensely long 
duration, e.g. an hour. 
An interesting point with regard to caffein- 
poisoning of Sarsia is, that as soon as spontaneity 
ceases the tentacles and manubrium lose their tonus 
and become relaxed to their utmost extent. This 
is not the case with anezsthesiation by chloroform, 
even when pushed to the extent of suspending 
irritability. If, however, Sarsiz which have been 
aneesthesiated to this extent in chloroform be 
suddenly transferred to a solution of caffein, the 
tentacles and manubrium may soon be seen to relax, 
and eventually these organs lose their tonus as 
completely as if the anzsthesia had from the first 
been produced by the caffein. Moreover in this 
experiment the irritability, which had been de- 
stroyed by the chloroform, returns in the solution 
of caffein—provided the latter be not quite satu- 
rated—though spontaneity of course remains sus- 
pended throughout. 
The effects of graduating the doses of caffein may 
be stated in connection with another species, viz. 
Tiaropsis diademata. In a weak solution the effects 
are a quickening of the pulsations (e.g. from 64 to 
