390 Boyal Society : — 



nihilation of the muscular current during muscular contraction when 

 the muscle contracts under the galvanic current, and that the con- 

 traction is seen to be most marked when this annihilation is most 

 complete. 



" Reflecting upon these facts and considerations," the author 

 continues, "there appears to be nothing in the history of ordinary mus- 

 cular contraction which does not harmonize with the electrical history 

 of rigor mortis. If the muscular current be present, rigor mortis is 

 absent ; and in this case it seems as if the state of muscular contrac- 

 tion is antagonized by the muscular current. In ordinary muscular 

 contraction, to all appearance, it is the same, and when the muscle 

 is relaxed the muscular or the artificial current is present, and when 

 the muscle is contracted the muscular curi'ent is weakened or anni- 

 hilated. It seems, indeed, as if the direct effect of the uninterrupted 

 current, whether natural or artificial, is to antagonize contraction ; 

 and that this is really the case may be argued finally from the fact 

 (recently discovered by Dr. Eckhard) that the state of tetanus 

 is put an end to bij the passage of a constant galvanic current 

 through the tetanized parts. 



" Nor is there any reason to suppose that the contraction is pro- 

 duced by a kind of correlative transmutation of electricity into con- 

 tractile force. In rigor mortis such an idea is scarcely tenable ; for 

 here the muscular current has died out slowly, and the contraction 

 has not supervened until the last traces have disappeared. In ordi- 

 nary contraction, it might be supposed that there had been some 

 transmutation of the muscular current into contractile force, or that 

 an electric discharge had served as a stimulus to some vital property 

 of contractility. But this idea is contradicted (this among other 

 ways) by the recent investigations of Dr. Harley upon the modus 

 operandi of strychnia. These investigations prove conclusively that 

 this poison acts by making the blood less able to appropriate oxygen, 

 and by impairing the irritability of the muscles. They prove, that 

 is to say, that strychnia produces contraction, by reducing the 

 amount of stimulus supplied in the blood, and by rendering the 

 muscles less capable of responding to any stimulus. I find also 

 that strychnia exercises a directly depressing influence upon the 

 nervous and muscular currents. I place the two hind limbs of the 

 same frog, properly prepared, one in a weak solution of strychnia, 

 the other in plain water, and, leaving them to themselves, I find that 

 the nerve and muscular currents have died out much sooner in the 

 limb which has been acted upon by the strychnia. Now, in this 

 case, the limbs have been left to themselves, and it cannot be said 

 therefore that the nerve and muscular currents have been changed 

 into contractile force by any kind of correlative transmutation. 

 Indeed, the facts would only seem to be intelligible on the suppo- 

 sition that, electrically considered, the strychnia has brought about 

 contraction according to the mode which has been set forth in the 

 preceding pages. Nor on this view is the fact less intelligible, that 

 the respiration of muscle is carried on more energetically in muscles 

 which are made to contract than in muscles which are allowed to 

 rest. Prof. Matteucci, who has recently ratified this fact by some 



