723 



dorsal vessel, which still persisted long after the loss of voluntary 

 power, was very irregular and segmental, the vessel being bloodless 

 and inert at intervals. 



It appeared indifferent whether the cephalic or the caudal ex- 

 tremity of the Nereis was attacked by the Actinia, similar symptoms 

 being produced in both cases. 



In order to ascertain how far these symptoms were produced by 

 electricity, I subjected the. Nereis enclosed in a glass tube to some 

 violent shocks by means of an electro-magnetic machine, which were 

 merely productive of a slight temporary inconvenience to the animal, 

 unattended by any after evil effects. It is most remarkable what 

 powerful electric action these creatures are susceptible of enduring 

 without injury ; the strongest action of an electro-magnetic machine 

 on Du Bois Reymond's principle, which affected myself violently up 

 to the elbows, appeared to be easily endured by them. 



The above experiment is quite sufficient to show how impossible it 

 is to attribute the fatal influence of the Actiniae to simple electrical 

 action. 



In order to elucidate the real power of the Actiniae after having 

 in vain exposed the finger on which the cuticle had been softened by 

 soaking in water considering that the tongue was better adapted 

 for the purpose in view, by reason of the thinness of its cuticle, I 

 presented its apex to the tentacles of an Actinia mesembryanthemum, 

 of about the size of a half-crown piece. The result was such as to 

 satisfy the most sceptical respecting the offensive weapons with 

 which it is furnished. The animal seized the organ most vigorously, 

 and was detached from it with some difficulty after the lapse of about 

 a minute. Immediately a pungent acrid pain commenced, which 

 continued to increase for some minutes until it became extremely 

 distressing. The point attacked felt inflamed and much swollen, 

 although to the eye no change in the part could be detected. These 

 symptoms continued unabated for about an hour, and a slight tem- 

 porary relief was only obtained by immersing the tongue in cold or 

 warm water. After this period the symptoms gradually abated, and 

 about four hours later, they had entirely disappeared. A day or two 

 after, a very minute ulceration was perceived over the apex of the 

 tongue, which disappeared after being touched with nitrate of silver. 



I have subsequently frequently repeated this experiment on myself 

 VOL. ix. 3 c 



