MEDICAL BATTERIES. 



81 



of extreme gravity? This fact led ine to the discovery of the 

 great excitability of the respiratory nerve of Bell, which I believe 

 to be the most excitable of all the nerves ; but this discovery, as 

 we have seen, cost me somewhat dear.*^ 



^ Kemak has criticised the experiment 

 ■which shows the great excitability of the 

 resi^iratory nerve of Bell, by m;iking, 

 and commenting upon, the experiments 

 following. He has placed a moist 

 rheophore over the occipital extremity of 

 the trapezius, and another over the spine 

 of the scapula, according to the direction 

 of the muscular iibres, and then passed a 

 moderate induced current, from which he ; 

 obtained only slight contractions. In 

 another experiment, he left one of the l 

 rheophores in its former position (either | 

 that at the occiput or that at the scapula), 

 and jjlaced the other over the border 

 of the trapezius, at the point of entry of 

 the accessory nerve of Willis. The same i 

 current then j^roduced elevation of the 

 shoulder and inclination of the head. | 

 He has made analogous experiments 

 upon the bice25S of the arm, and has 

 obtained similar results, that is to say, a 

 contraction of the muscle en masse, from 

 excitation of its motor nerve, and very 

 weak contractions when the rheoi^hores 

 were placed over the extremities of the 

 muscle. The only rational conclusion to 

 be drawn from these exjjeriments is that 

 excitation of a motor nerve produces 

 contraction of all the fibres to which it 

 is distributed (aud hence a considerable 

 movement) ; while faradization of the 

 parts of a muscle remote from the points 

 of immersion or emergence of a motor 

 nerve, produces contraction only of those 

 fibres tliat are in relation with the rheo- 

 phores, and of these only the more super- 

 ficial if the tension of the current be 

 slight; whence a feeble and limited 

 movement. By acting alternately upon 

 bare muscle, and upon its nerve, it may 

 be seen that this conclusion is perfectly 

 correct. It is, therefore, not surprising 

 that direct faradization shoidd produce 

 less movement than indirect; since a 

 much smaller number of muscular fibres 

 are thrown into contraction by the 

 former. Moreover, in these experiments 

 of M. Eemak, the rheophores were placed 

 at the extremities of the muscle (at the 

 occipital extremity of the trapezius and 

 on the spine of tlie scapula, and in the 

 same way for the biceps), that is to say, 

 over structures in great part ajioneiirotic or 

 tendinous, so that the contractions would 

 necessarily be feeble, because only a few 

 muscular fibres would be in relation with 

 the rheophores. If M. Remak had placed 



his rheophore entirely upon muscular 

 fibre, — for instance, a little above the 

 middle portion of the border of the tra- 

 pezius,— I am sure that he would have 

 l^roduced a marked contraction of the 

 clavicular portion of the muscle, which 

 he evidently could not obtain whilst the 

 rheophores were placed over the apone- 

 m-otic extremities. 



It is plain that it would be difficult 

 to deduce any strict conclusion from 

 exi>eriments so badly jierformed. We 

 shall see, however, from his manner of 

 interpreting them, how ardent is the 

 imngination of M. Eemak. In the first 

 place, he fails to see that the difference 

 in the movements obtained in the 

 several experiments dei^ends upon the 

 fact that, in the one case, the excitation 

 of the muscular nerve causes the con- 

 traction of all the fibres to which it is 

 distributed; while in the other, only a 

 small number of fibres, namely those in 

 the neighbourhood of the aponeurosis, 

 are situated beneath the rheophores, and 

 thus called into contraction. Every one 

 else would conclude from this that the 

 tendinous or aponeurotic fibres, in their 

 normal state, are not irritable; but M. 

 Remak, taking the aponeurotic for mus- 

 cular fibres, draws from his experiments 

 the following deduction against the 

 Hallerian contractility. " That which 

 strikes us the most," he says, '' is that 

 these experiments, besides their practical 

 significance" (this practical significance 

 being, according to M. Eemak, that the 

 electric current should be exclusively 

 directed upon the motor nerve at its 

 point of immersion or emergence— a 

 retrograde precejjt as I have shown) 

 " contribute essentially to the solution of 

 the question, respectable by its antiquity, 

 of the so-called irritability." The solu- 

 tion of which M. Remak wishes to speak, 

 is the reversal of the doctrine. A little 

 above, in fact, introducing irrelevantly the 

 question of the doctrine of irritability, he 

 has said, " It is scarcely necessary for me 

 to point out how little these physiological 

 experiments justify the pretended doctrine 

 of Hallerian irritability." 



If M. Eemak has only such arguments 

 as these in opposition to the Hallerian 

 irritability, that doctrine has nothing to 

 fear from his attacks. The micrographics 

 physiologist should know, better than 

 any one, that such a question can only 



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