128 Electricity and Galvanism. 



Shortly after the announcement of this discovery, Prof. Volta, 

 of Pavia, in repeating this and other analogous experiments, arrived 

 at a different conclusion; and he showed that the electricity was 

 really excited by the metals, and the contraction of the muscles 

 of the frog was only an index of its existence. Although these and 

 other discoveries of that great man obscured for a time the views and 

 researches of the illustrious Galvani, attention was again drawn 

 to them by the experiments of his talented nephew, Prof. Aldini, of 

 Bologna. He was inspired with so much zeal in the defence of 

 his uncle's theory, that he travelled through France and England for 

 the purpose of demonstrating the truth of his views ; and, in the 

 presence of the medical officers and pupils of Guy's Hospital, he, in 

 the year 1803, supported and defended a series of propositions so 

 satisfactory and conclusive, that he was presented by his auditors 

 with a gold medal commemorative of his labours. On leaving Eng- 

 land, these propositions, and the arguments in support of them, were 

 published in a quarto volume, which seems to have attracted but 

 little notice either here or on the continent of Europe. Scarcely any 

 mention is made of Aldini by more modern writers ; and not many 

 weeks ago I removed the volume from the library of the Royal 

 Medical and Chirurgical Society with its leaves uncut. 



Prof. Aldini' s propositions and conclusions are so important and 

 of such high interest, that I shall now briefly refer to some of them, 

 as they demonstrate to my mind, in a most satisfactory manner, 

 the existence of free electricity in animals, and, as will appear to 

 all conversant with this branch of physiology, most remarkably anti- 

 cipate the late researches of his countryman, Prof. Matteucci. 



Prop. I. — Muscular contractions are excited by the development 

 of a fluid in the animal machine, which is conducted from the nerves 

 to the muscles without the concurrence or action of metals. 



Exp. A. — In proof of this statement, Aldini procured the head of 

 a recently-killed ox. With the one hand he held the denuded legs of 

 a frog, so that the portion of the spine still connected with its lumbar 

 nerves touched the tip of the tongue, which had been previously 

 drawn out of the mouth of the ox. The circuit was completed by 

 grasping with the other hand, well moistened with salt and water, 

 one of the ears. The frog's legs instantly contracted; the contrac- 



