1892.] Adductor Fibres of the Recurrent Laryngeal Nerve. 103 



subjects who died of cholera, found that the crico-arytenoideus 

 posticus muscles were the first to lose their excitability after death. 

 This observation has been abundantly confirmed by Horsley and 

 Semon* for all classes of animals. On the other hand, ether, reach- 

 ing the laryngeal muscles through the circulation, puts the adductors 

 into abeyance before the abductors, so that, while excitation of the 

 recurrent nerve of an animal not very deeply under its influence 

 results in adduction of the corresponding vocal cord, similar excita- 

 tion of the nerve when the animal is profoundly under the influence 

 of the anaesthetic results in abduction of the cord.f It seemed, 

 therefore, not unlikely that, if the fibres dominating over the one 

 function could be successfully separated from those dominating over 

 the other, some fresh light might be thrown on this subject. 



It is interesting to find that Dr. Felix Semon, J in a paper written 

 so long ago as 1881, asked the following question with regard to the 

 fibres of the recurrent laryngeal nerve : " Are we to suppose that, 

 though the nerve is apparently homogeneous, it consists in reality of 

 a bundle of strictly differentiated fibres, bound together simply by 

 a common nerve sheath, and actually differentiated throughout their 

 peripheral course ; in fact, having ganglionic centres of their own ? " 

 Dr. Semon then goes on to show that the pathological facts strongly 

 support the probability of the truth of this hypothesis. § 



Morell Mackenzie, || in his text-book published the year before 

 Semon raised this question, suggested that possibly the abductor 

 filaments were more superficially situated than the adductor fibres, 

 and that this, if true, would account for the proneness of the abduc- 

 tors to succumb before the adductors in affections, especially com- 

 pression by tumours, of the nerve. There is, however, no ground for 

 this hypothesis. 



Since then, the general question of the proclivity of the abductor 

 fibres has been the subject of great controversy, and has been 

 debated both from a clinical and pathological standpoint,^ but, so 

 far as I am aware, very few attempts have been made to determine 



* 1 British Medical Journal,' Aug. 28 and Sept. 4, 1886. 



f Hooper, ' Trans, of the Amer. Laryngol. Assoc.,' vol. 7 ; Horsley and Semon, 

 ' British Medical Journal,' Sept. 4 and 11, 1886. 



X Semon, ' Arch, of Laryngology,' 1881, vol. 2, p. 200. 



§ Dr. Semon's views have been amply confirmed by direct experiments on the 

 cortical and bulbar centres for the laryngeal muscles. See history of the subject in 

 paper by Semon and Horsley, ' Phil. Trans.,' 1890. 



|| Mackenzie, 'A Manual of Diseases of the Throat and Nose,' 1880, vol. 1, 

 p. 440. 



% For a full history of this, see Semon's contribution to the ' Yirchow-Fest- 

 schrift ' ; " Die Entwicklung der Lehre von den motorischen Kehlkopflahmungen 

 seit der Einfuhrung des Laryngoscops," 1891. 



