140 



SPECIAL PHYSIOLOGY. 



might be called its equator, 1, e, to the centre or axis, d, of both of 

 its two cut extremities or poles. From points of the longitudinal sur- 

 face more or less distant from the equator, to points of the ends more 

 or less distant from the axis, the direction of the currents is still the 

 same, but they are proportionally weaker, 2. When two points on the 

 longitudinal surface, equidistant from the equator, are touched, 3, no 

 current is evident, an equilibrium being established; but when two 

 points unequally distant from the equator, are touched, 2, a feeble 

 current is manifested from the nearer to the more distant point. In 

 the same way, two points, at either cut end, equidistant from the axis, 

 3, give no apparent current; but if unequally distant from it, 2, they do. 

 To explain these remarkable electrical currents of the living mus- 

 cular substance, it has been suggested by Du Bois-Reymond, that it 

 possesses a peculiar electrical condition, which is supposed to be de- 

 pendent on a special electrical polarity of the component molecules or 

 the disdiaclasts of the sarcous elements. Each molecule, in a given 

 longitudinal row, Diagram D, is imagined to have its equatorial or 

 central part positive, -J-, and its two ends, or poles, opposed to the 

 neighboring molecules, negative, . In this case, a current would 

 pass outside the molecules, from the equator to the poles, but, within 



Diagram D. 



Diagram D (Du Bois-Reymond) shows the theoretical electrical condition of the molecules of muscular 

 tissue. Each molecule in a series, is supposed to be peripolar, the adjacent ends or poles being negative or 

 minus ; and the central or equatorial part, positive or plus +. The plus portion is shown white and is 

 marked + ; the minus parts are left black, and are marked . The arrows show the necessary directions 

 of the normal currents outside such an arrangement. 



the molecules, from the poles to the equator. Each molecule, in such 

 case, would represent, in miniature, the electrical condition of the en- 

 tire piece of muscle. This supposed condition of the molecules is 

 named a peripolar electrical state. It exists in an artificial molecule 

 made with a zinc equator and copper ends or poles, when immersed in 

 dilute acid. 



The muscular current in amputated limbs, also passes from the side 

 of the limb to the cut extremity. It is manifested, as already men- 

 tioned, in even the smallest fragments of muscle, and also in the fibres 

 of the heart, and in the non-striated muscular tissues. It remains for 

 a time, though weaker, even when the contractility has already disap- 

 peared. In an entire muscle, the ends of which are not cut, it is stated 

 by Du Bois-Reymond, that the currents have still the same direction, 

 passing outside the muscle, through the galvanometer, from the sides 

 or natural longitudinal surface, to the ends or tendons, or natural 

 transverse surfaces of the muscle. In entire limbs, the current sup- 

 posed to be the resultant of the combined currents of the several mus- 

 cles, runs, in the case of the frog, from the tips of the toes to the trunk, 

 and, in the case of the entire body, from the coccyx to the head ; this 



