424 Dr. F. Semon. On tlie Position of the 



described cases of bilateral paralysis of the recurrent laryngeal 

 nerves (which, are extremely rare) agree that there is no dyspnoea when 

 the patients are at rest ; but then two circumstances combine to 

 render the value of this statement rather doubtful for the decision of 

 the point here at issue. 



In the first place, it is more than likely that only those coarser 

 differences of respiration which are termed " eupncea " and " dyspnoea" 

 respectively have met with attention on the part of clinical observers, 

 and that, as no actual dyspnoea in the clinical sense of the term was 

 met with in such patients when at rest, finer differences in the type 

 of respiration, such as intensification or acceleration of respiratory 

 movements on very slight exertion, were not particularly studied. 

 Moreover, some of these observers, as for instance Solis Cohen,* 

 indeed, speak of " moderate dyspnoea " on exertion occurring some- 

 times under such circumstances. 



Secondly, however, a very important element, not mentioned so 

 far, here comes into consideration, namely, the wonderful adaptability 

 of the human organism to very considerable changes in the respi- 

 ratory conditions, provided that these changes are produced slowly. It 

 is an every- day observation with laryngologists, that an acute stenosis 

 of the larynx, such as produced, for instance, by acute oedema, inter- 

 feres, even if by no means very considerably, yet in a much higher 

 degree, with respiration, and produces much greater subjective and 

 objective dyspnoea, than a much higher degree of stenosis due to 

 chronic affections, such as growths in the larynx, bilateral paralysis 

 of the glottis openers, cicatrices after ulcerative disease, congenital 

 membranes expanded between the vocal cords, &c. 



Now in almost all cases in which bilateral paralysis of the recur- 

 rent laryngeal nerves (i.e., the pathological equivalent during life to 

 the 'cadaveric position of the glottis after death) is produced, the 

 coarse of events is a very slow one, and the patients have ample 

 time to adapt their entire respiratory mechanism to the altered con- 

 ditions of the larynx. Under such circumstances, their whole mode 

 of respiration is instinctively changed to such a degree, that the 

 effects of the reduction of the glottis to the cadaveric size are not 

 likely to attract prominent attention. 



Yet there can be no doubt in my opinion that in cases of reduction 

 of the glottis to the cadaveric size, except when the act of respiration 

 is 'at its lowest physiological ebb, i.e., during complete rest of the body, 

 a modification of the mechanism of respiration does occur as soon as 

 any demand is made upon the respiratory apparatus. 



This opinion is not purely theoretical. 



I have never had the opportunity of observing a case of quite com- 

 plete bilateral paralysis of the recurrent laryngeal nerves, but I have 



* Loo. cit., p. 144. 



