POISONS. 223 
themselves or to the neuro-muscular tissue of the 
bell. Death always takes place in very strong 
systole; and as this is an exceedingly unusual thing 
in the case of Sarsia, there can be no doubt that, 
in this respect, the action of the digitalin is different 
on the Medusze from what it is on the heart. 
On the various species of Tiaropsis, digitalin at 
first causes acceleration of the swimming move- 
ments, with great irregularity and want of co- 
ordination. Next, strong and persistent spasms 
supervene, which give the outline of the necto- 
calyx an irregular form; and every now and then 
this unnatural spasm gives place to convulsive 
swimming motions. Evidently, however, the spasm 
becomes quite persistent and excessively strong. 
The manubrium of Tiaropsis indicans crouches to 
its utmost, and the animal dies in strong systole. 
7. Atropin.—In the case of Sarsia atropin causes 
convulsive swimming motions. The systoles next 
become feeble, and finally cease. The nectocalyx 
is now somewhat drawn together in persistent 
systole, with the manubrium and tentacles strongly 
retracted. Muscular irritability remains after ten- 
tacular irritability has disappeared, but it is then 
decidedly enfeebled. 
In the various species of Tiaropsis the convulsions 
are strongly pronounced. They begin as mere 
accelerations of the natural swimming motions, 
but soon grow into well-marked convulsions, con- 
sisting of furious bouts of irregular systoles follow- 
ing one another with the utmost rapidity, and 
wholly without co-ordination. Occasionally these 
