“I prepared several legs of frogs in such a manner that a portion of the crural nerve and a part of the muscle of the same length were left dependent. I placed a glass tube in a horizontal direction above a vessel containing mercury; made fast to it two silk threads, and suspended from it the thigh of the leg in such a manner that the nerve and muscle could be made to descend at pleasure. I brought the leg of the frog within two lines of the vessel, and then lengthened the thread till the nerve touched the surface of the metal. No contractions took place; but as soon as the nerve also was brought into contact with the metal, by lengthening the silk thread, the whole limb experienced a convulsive shock. I repeated this experiment with the same precaution, employing the two other vessels, and the same results were obtained. “The muscle and nerve touched the mercury only at the surface; they were in no manner immersed in the metal; and care had been taken to lower them so gently, that it was impossible to suspect there could be any impulse, as in the experiment where Aldini had caused the mercury to flow down by employing a vessel shaped somewhat like a syphon.” APPENDIX. No. I. _An Account of the Experiments performed by J. Aldini on the Body of a Malefactor executed at Newgate Jan. 17th 1803._ INTRODUCTION. The unenlightened part of mankind are apt to entertain a prejudice against those, however laudable their motives, who attempt to perform experiments on dead subjects; and the vulgar in general even attach a sort of odium to the common practice of anatomical dissection. It is, however, an incontrovertible fact, that such researches in modern times have proved a source of the most valuable information, in regard to points highly interesting to the knowledge of the human frame, and have contributed in an eminent degree to the improvement of physiology and anatomy. Enlightened legislators have been sensible of this truth; and therefore it has been wisely ordained by the British laws, which are founded on the basis of humanity and public benefit, that the bodies of those who during life violated one of the most sacred rights of mankind, should after execution be devoted to a purpose which might make some atonement for their crime, by rendering their remains beneficial to that society which they offended.