294? Intelligence and Miscellaneous Articles. 



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of a millimetre. They are placed in juxtaposition in the cylinder 

 and united so closely that they appear to a common observer to form 

 a homogeneous mass. 



At the surface of the muscular fibres just described, we perceive 

 some rings, which surround their entire circumference like small 

 ribands ; they are about ^^ of a millimetre apart from each other 

 upon the fibre when it has lost all its irritability, closer on the 

 living fibre : these rings belong to the enveloping membrane. If this 

 latter becomes fissured longitudinally, which at times occurs, we 

 observe the longitudinal fibrillse which form its mass, project in the 

 fissure. The torn portions of the rings enable us to observe the ends 

 of the reticula of which they are composed, and which cannot be seen 

 in the normal state. 



On illuminating the muscular fibres by means of a mirror which 

 reflects the light upon their upper surface, we observe that the 

 nervous reticula which ramify on the muscle enter the linings of 

 the fibres ; they thus appear to surround them similar to a series of 

 circularly curved handles (ansae). The fibres in their quiescent state 

 'are not straight but slightly curved. When they act, every portion 

 of the broken line which they present gravitates the one against the 

 other, and the muscular contraction results from the shortening 

 produced by this action. Such are the facts which every one may 

 observe with a good microscope. 



Now let us apply to this highly remarkable anatomical arrange- 

 ment, the doctrine of electric currents along the nervous reticula. 

 It is evident that in this case each fibre becomes a little magnet 

 with a flexible joint, the various parts of which would tend recipro- 

 cally to attract each other, and would produce the eff^ect which we 

 observe in the muscular contraction. But how detect these currents ? 

 Hitherto they have been sought for only with the electrical multi- 

 plier ; and we could not expect to find anything, as we had to do 

 with closed circuits, and knowing at the same time that a divided 

 nerve does not transmit any action. There was nothing left there- 

 fore but the magnet that could point them out to us. To employ 

 the magnetic needle was rather a difliicult affair : I had recourse to a 

 diff'erent means. 



If a needle is placed in contact with some finely divided filings, 

 such as we obtain from a file and soft iron, be it ever so slightly 

 magnetic, it is perceptible from the arrangement which the particles 

 of iron take at its surface : they plant themselves as little needles, 

 which arrangement is easily perceptible with a magnifier. We must 

 not confound this action with the attraction by which minute bodies 

 remain attached to a bar with which they are touched. I ran a very 

 fine needle not magnetized into the thigh of a frog, following the 

 direction of the fibres ; the point projected and dipped into the filings. 

 At the moment when I excited a violent contraction by wounding the 

 spinal marrow, I saw the small particles of iron arrange themselves 

 at the point of the needle as they do when it is magnetic ; they dis- 

 appeared with the irritation of the muscle. 

 By further investigating this phsenomenon I hope to render it very 



