POISONS. 223 



themselves or to the neiiro-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 ditferent 

 on the MedusD3 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 

 SAvimming 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 



