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a modification of the foregoing experiments ; for although irritants, 

 such as turpentine, croton oil, ammonia, friction with a nettle leaf, 

 &c., were applied to the nerves without producing any effect like 

 that obtained from the actinise, it seemed still possible that the con- 

 tractions might be due to some other agent than electricity. 



The following experiment seems to remove all doubt. A piece of 

 copper wire, a few inches long, was coated with sealing-wax, except 

 about half an inch at each end; the ends were rubbed clean with 

 sand-paper, one of them was thrust into the lower part of the spinal 

 canal of a frog prepared as in the last experiment, while the other, 

 which was to be offered to an actinia, was passed into a portion of 

 the frog's intestine put on like a glove ; for the actinia does not 

 seize vigorously metallic substances. The limbs of the frog with the 

 nerves and vertebree attached, are laid on a piece of board, while the 

 copper wire, which is curved, arches over the edge of it ; so that the 

 end covered with frog's intestine can be readily brought within the 

 reach of the actinia. Having waited for a few minutes until the 

 muscular contractions excited by thrusting the wire into the spinal 

 canal have ceased (and they are in general very transient), the board 

 is placed floating on the water, and the frog's intestine offered to an 

 actinia; muscular contractions ensue, perhaps not so promptly, 

 certainly not so vigorously as in the former experiments, but never- 

 theless easily to be recognized and unmistakeable. They commence 

 in the thighs, and, as in the former case, extend to the calves, and 

 then the toes move actively. This last experiment has been modified 

 in a variety of ways, but the same result has been constantly obtained. 

 Perhaps the best modification of it is to use a piece of copper wire 

 having one end coiled so as to form a disk which is covered with 

 chamois-leather, while the other is sharp-pointed to enter the spinal 

 canal of the frog. The whole, except the surface of the disk, which 

 is to be given to the actinia, and the point for the spinal canal, is 

 covered with sealing-wax, and the frog's limbs extended upon a thin 

 piece of board. With this arrangement precisely the same effects 

 were produced as already described. 



It is a remarkable fact, and deserves special notice, that in all 

 these experiments the muscular contractions, when once strongly 

 excited, whether by direct contact or through the medium of wire, 

 do not at once subside. When the limbs are withdrawn from the 



