324 PEESENT STATE OF ORGANIC ELECTRICITY. 



with masses, or aggregates of muscle, and had not attempted 

 to ascertain the laws of electric action in the muscular fibre 

 or bundle itself, or in a single isolated muscle.* 



These laws have been investigated by Du Bois Eeymond, 

 who has ascertained that muscular structure presents two 

 distinct electric conditions firstly, during the intervals of 

 contractions ; and secondly, during contraction. 



Electric Condition of a Muscle during the intervals of con- 

 traction. Galvani conceived the outer surface of a muscle to 

 be charged with negative, the inner with positive electricity. 

 Matteucci had found that in order to produce contractions in 

 the galvanoscopic frog, two parts of its nerve must be brought 

 into contact with two parts respectively of the muscle of a 

 living animal ; and that the experiment uniformly succeeded 

 if the nerve touched the bottom of a wound in the muscle and 

 the margin of the wound at the same time. Du Bois Eey- 

 mond has ascertained the actual relative electric condition of 

 certain surfaces or aspects of the muscular fibre or muscle.t 

 These aspects he denominates the longitudinal and transverse 

 sections. These sections, again, may be either natural or 

 artificial. 



The natural longitudinal section is as much of the surface 

 of a muscle as is formed by the exposed sides of its superficial 

 fibres. 



An artificial longitudinal section is any surface exposed 

 by a section in the direction of the muscular fibres. 



The surface or side of a fibre or fasciculus viewed as a 

 cylinder or prism is its longitudinal section. 



A natural transverse section is any part of a muscle formed 

 by the extremities of its fibres, coated by tendon of attachment. 



* Bib. Univ. de Geneve; Ann. de Ckim. et de Phys. ; Traite des Pheno- 

 m&nes Electro-physiologique. 



t " The Law of the Muscular Current," p. 498, vol. i. of Untersuch. ueber 

 Thier. Elcctridtdt. 



