74 



PHYSIOLOGY 



CHAP. 



These observations show that the natural surface of the muscle 

 has a positive electrical charge, which is maximal along the 

 equatorial line and decreases regularly away from it ; and that the 

 two artificial cross-sections have a negative electrical charge which 

 decreases regularly from the axial point of the muscle cylinder, 



Fio. 48. Diagram of direction of currents that 

 can be led off to a galvanometer from 

 different points of the surface of a muscle 

 cylinder. 



Fia. 49. Distribution of positive electrical 

 charge on natural longitudinal, and negative 

 electrical charge on artificial transverse 

 sections of a muscle cylinder. 



where it is maximal, to the more peripheral points of the cross- 

 section (Fig. 49). 



If the section is made obliquely through the muscle cylinder, 

 the potential at the different points of the natural surface and the 

 artificial surfaces varies according to another law. The galvano- 

 meter shows that the most positive points of the longitudinal 

 surface lie much nearer the obtuse angles of the rhombus, and the 

 more negative points close to the acute angles. The strongest 

 current is obtained on leading-off from these opposite points ; on 



+ 4- 4- 



FIG. 50. Diagram of direction of currents led 

 off from surface of a muscle rhombus. 



Fio. 51. Positive and negative electrical 

 charges at longitudinal and transverse 

 sections of a muscle rhombus. 



connecting points more remote from these the currents become 

 increasingly weaker ; lastly, there is no current on joining up 

 homonymous points on the natural or artificial surfaces (Fig. 50). 



There is thus in the oblique muscle cylinder a displacement of 

 the isoelectric equatorial and axial points in the direction indicated 

 in Fig. 51. 



The longitudinal surface of a muscle shows a positive charge 



