THE MUSCULAR CURRENT. 285 



the muscular current, occurring some time after death in piles composed of the same 

 number of muscular elements, but taken from different animals, as frogs, eels, or 

 pigeons. The signs of the current diminish in a rapid ratio as we ascend in the scale 

 of animals upon which we operate. 



Hitherto I have merely exhibited experiments which confirm my former conclu- 

 sions. I have simply sought to show how that without a very delicate galvanoscope, 

 and with the galvanoscopic frog alone, any person may be enabled to demonstrate 

 the principal laws of the muscular current. 



It has always been an object of peculiar interest to me, in the study of the mus- 

 cular current, to establish fresh experimental proof, or to repeat and extend my 

 former ones ; all which have led me to conclude that the existence and intensity of 

 the muscular current depend upon the existence and intensity of the changes of 

 structure and composition, which constitute the nutrition of the muscle. 



Nevertheless, before entering upon the exposition of my researches instituted in 

 this view, I will describe some fresh facts, which, although they may be anticipated, 

 notwithstanding, better serve to fix the origin of the muscular current. 



With a pile of half thighs of frogs I have distinctly obtained the decomposition of 

 iodide of potassium. To effect this, I soak a piece of paper in a solution of this sub- 

 stance, and upon it, about the distance of a line apart, I place the extremities of two 

 platinum wires, the other ends of which dip in the fresh water which fills the extreme 

 cavities of the pile. To facilitate and expedite the decomposition of the hydruret, 

 I increase the extent of those portions of the platinum wires which are immersed 

 in the cavities of the pile, by twisting the extremities into a coil ; I am also in the 

 habit of further wetting the paper soaked with the solution of hydruret of potassium, 

 with a solution of starch paste, to which I add a few drops of chlorine. After the 

 circuit has remained closed a few seconds, a blue or a yellow spot is formed around 

 the wire which communicates with the cavity in which the external surface of the 

 muscle is immersed. 



With a pile of twenty elements of half thighs of frogs, I have likewise distinctly 

 obtained signs of tension, by means of a tolerably delicate condenser. To this in- 

 tent I put one extremity of the pile in communication with the ground, and the other 

 with the plate of the condenser. I have frequently repeated the experiment, at one 

 time establishing a communication between the internal surface of the muscle and 

 the condenser, and the external surface with the ground ; at another time I have re- 

 versed this order. I have likewise observed the phenomena which ensue on putting 

 each of the extremities of the muscular pile in communication with one of the plates 

 of the condenser. In every case the electroscope has constantly exhibited signs of a 

 negative charge upon the internal surface of the muscle, and of a positive charge 

 upon the external surface. 



Again, I was desirous of ascertaining how the signs of the muscular current were 

 affected on excluding the air from contact with the pile. For this purpose I em- 



2 p 2 



