426 Dr. F. Semon. On the Position of the 



laryngeal nerves appear to have been damaged during the operation. 

 Unfortunately, however, the reports are in part incomplete, and 

 moreover the alterations in the calibre of the trachea due to the 

 previous direct compression by the constricting goitre also appear 

 to have in many of them played a considerable part in the production 

 of the respiratory phenomena observed after the operation. Thus 

 these cases are by no means pure, and can hardly be made use of for 

 a decision of the question at issue. The most important of them 

 perhaps is one reported by Riedel,* in which, either due to inunda- 

 tion of the wound with carbolic acid solution, or, as would seem more 

 probable, to tearing of the recurrent laryngeals in the course of the 

 operation, within two hours from its end dyspnoea developed. Still 

 even in this case evidence is not pure, as one of the pneumogastric 

 nerves was simultaneously damaged, and the dyspnoea may have been 

 in part referable to this cause. 



Thus pathological observation on the human subject so far offers a 

 much less complete reply to the question concerning the effect 

 of the reduction of the glottis to the cadaveric width than might 

 be theoretically expected, and this point will certainly demand con- 

 tinued attention. 



All that can at present be fairly said, is that the evidence points in 

 the direction that reduction of the glottis to the cadaveric size 

 involves, upon the commencement of any effort, however small, some 

 alteration in the type of respiration. 



Although the evidence concerning the effects upon the respiration 

 in man of the interpolation of the phonatory apparatus leaves a good 

 deal to be desired, as shown in the last two chapters, there can be no 

 doubt, I think, that its whole tenour goes to show, as would, indeed, 

 be expected from the anatomical facts above demonstrated, that this 

 interposition presents a considerable hindrance to the function of 

 quiet respiration, and that for the fulfilment of the latter function it 

 had to be counterbalanced or neutralised to a certain degree. 



This neutralisation could evidently have been effected in one of 

 two forms, namely, either in the form of a rhythmical widening and 

 closure of the glottis, such as commonly is supposed to exist even 

 during tranquil respiration, or in the form of a tonic dilatation of the 

 glottis during both phases of quiet respiration (inspiration and 

 expiration), supplying the minimum of space compatible with the 

 ingress and egress of that amount of air to the lower air passages 

 which is required for the purposes of what we call normal quiet 

 respiration. 



It has been shown in the preceding chapters that both these 

 alternatives are actually met with in the quiet respiration of men, 

 and it is hardly necessary to say that they do not in the least exclude 

 * ' Centralblatt fur die med. Wiss.,' 1882. 



