ZOOLOGICAL AND BOTANICAL ASSOCIATION. 57 



On the hypothesis that it is an electrical power with which the Actiniae 

 are endowed, it is obvious that the existence of animal electricity in 

 them ought to be experimentally demonstrable by its physiological effects* 

 inasmuch as these phenomena are the most striking which animal elec- 

 tricity is capable of producing in common with other electricities derived 

 from different sources. 



The following experiments, in which the frog's limb was used as a 

 galvanometer (the limb of this animal being, as is well known, an in- 

 strument of extreme delicacy for this purpose), seem satisfactorily to 

 establish the fact, that the common Actiniae of our shores arc gifted with 

 electrical power. 



1st Having prepared the lower limb of a lively frog after the mode 

 described by Matteucci, by stripping off the skin, dissecting out the 

 sciatic nerve from among the muscles of the thigh, and then cutting off 

 the thigh a little above the knee, so as to leave the nerve uninjured and 

 as long as possible, the limb was laid on a small piece of glass, so that 

 the nerve hung down over its edge. The pendant nerve was lowered 

 into the water and gently brought in contact with the tentacles of an 

 expanded Actinia. From the first, or the second, or even several, pos- 

 sibly no effect may result. But, arriving at last at one more vigorous 

 than his neighbours, smart muscular contractions follow as it grasps the 

 nerve in its tentacles, and the toes are thrown into active movement. 



2nd. The next experiment, although of precisely the same nature 

 as that just detailed, renders the effect produced on the muscles of tho 

 frog's limb more striking. A large and lively frog is killed, the skin is 

 stripped off, and the viscera being removed, the body is cut off about 

 the middle : slipping a knife behind the lumbar plexus of nerves, the 

 pelvis and contiguous soft parts are cut away, so that the lumbar ver- 

 tebrae remain connected with the lower extremities merely by the two 

 nervous cords passing to each limb. Thus prepared, the limbs are laid 

 on a thin piece of board, so that the vertebrae hang over its edge dangling 

 by the undivided nerves. 



The piece of board is placed floating on the surface of the water in 

 which are the Actinia, and is slowly pushed over within reach of an 

 active one. Immediately that tho Actinia seizes the morsel thus offered 

 to it, contractions are observed to commence in the thigh, extend to the 

 calf, and soon the toes are in movement. 



ZOOL. 4 BOT. PROC. 80C — VOL. I. I 



