ELECTRICAL THEORY OF MUSCULAR CONTRACTION. 403 



is produced by electricity. The former, which was originally propounded 

 by Girtanner, 1 and zealously embraced by Dr. Beddoes, who was more 

 celebrated for his enthusiasm than for the solidity of his opinions, has 

 now few supporters. This hypothesis supposes, that muscular contrac- 

 tion depends upon the combustion of the combustible elements of the 

 muscle, hydrogen and carbon, by the oxygen of the arterial blood; the 

 combustion being produced by the nervous influx, which acts in the man- 

 ner of an electric spark ; at least, such is the view adopted by M. 

 Richerand, 2 one of the most fanciful of physiological speculators. Of 

 course, we have neither direct nor analogical evidence of any such com- 

 bustion, which, if it existed at all, ought to be sufficient, in a short space 

 of time, to entirely consume the organs that furnish the elements. 

 The idea is as unfounded as numerous others that have been enter- 

 tained, and is worthy only of particular notice, from its being professed 

 in one of the well-known works on physiological science. 



The second hypothesis refers muscular contraction to electricity. 

 Attention has been already directed to the electroid or galvanoid cha- 

 racter of the nervous agency ; and we have some striking examples on 

 record of the analogous effects produced by the physical and the vital 

 fluid on the phenomena under consideration. It has been long known, 

 that when nerves and muscles are exposed in a living animal, and 

 brought into contact, contractions or convulsions occur in the latter. 

 Galvani 3 was the first to point this out. He decapitated a living frog; 

 removed the fore-paws, and quickly skinned it. The spine was divided, 

 so as to leave the spinal marrow communicating only with the hinder 

 extremities by means of the lumbar nerves. He then took, in one hand, 

 one of the thighs of the animal, and the vertebral column in the other, 

 and bent the limb until the crural muscles touched the lumbar nerves. 

 At the moment of contact the muscles were strongly convulsed. The 

 experiment was repeated by Volta, 4 Aldini, 5 Pfaff, 6 Humboldt, 7 and 

 others ; and with like results. Aldini 8 caused convulsions in the mus- 

 cles by the contact of those organs with nerves, not only in the same 

 frog, but in two different frogs. He adds, that he remarked them 

 when he put the nerves of a frog in connexion with the muscular flesh 

 of an ox recently killed. Humboldt made numerous experiments of 

 this kind on frogs, and found convulsions supervene when he placed 

 upon a dry plate of glass a posterior extremity whose crural nerves had 

 been exposed, and touched the nerves and muscles with a piece of raw 

 muscular flesh, insulated at the extremity of a stick of sealing-wax. 

 Convulsions likewise occurred, when, instead of one piece of flesh, he 

 used three different pieces to form the chain, one of which touched the 

 nerve ; the other the thigh, and the third the two others. The expe- 

 riments were repeated by Ritter with similar results ; but they were 



' Journal de Physique, xxxvii. 139. 2 Elements of Physiology, 163. 



3 Mem. sull' Elettricita Animate, Bologn., 1797. 



4 Memoria sull' Elettricita Animale, 1782. 



6 Essai Theoretique et Experiment, sur le Galvanisme, Paris, 1804. 

 Ueber thierische Electricitat und Reizbarkeit, Leipz., 1795. 



7 Versuche iiber die gereizte Muskel und Nervenfaser, Posen und Berlin, 1797. 



8 Traite cornplet de Physiologic de 1'Homme, par Tiedemann, traduit par Jourdan,p. 559, 

 Paris, 1837. 



