234 JELLY-FISH, STAR-FISH, AND SEA-URCHINS. 
that which we employ when administering them to 
other animals; for, in the case of the Medusz, the 
neuro-muscular tissue is spread out in the form of 
an exceedingly tenuous sheet, so that when the 
animal is soaking in the poisoned water every por- 
tion of the excitable tissue is equally exposed to its 
influence ; and that the action of a poison is greatly 
modified by such a difference in the mode of its 
administration has been proved by Professor Gamgee, 
who found that when a frog’s muscle is allowed 
to soak in a solution of vanadium, etc, it loses 
its irritability, while this is not the case if the poison 
is administered by means of the circulation. 
I may further observe that in the case of all 
poisons I have tried, the time required for recovery 
after the animal is restored to normal water varies 
immensely. The variations are chiefly determined 
by the length of time during which the animal has 
been exposed to the influence of the poison, but 
also, in a lesser degree, by the strength of the solu- 
tion enployed. To take, for instance, the case of 
eaffein or chloroform, if Sarsiz are transferred to 
normal water after they first cease to move, a few 
seconds are enough to restore their spontaneity ; 
whereas, if they are allowed to remain in the 
poisoned water for an hour, they may not move 
for one or two hours after their restoration to un- 
poisoned water. In consequence of such great varia- 
tions occurring from these causes, I was not able 
to compare the action of one poison with that of 
another in respect of the time required for effects 
of poisoning to pass away. 
