ON ANAESTHETICS 145 
obstruction, as some have supposed, had its anterior edge directed forwards : 
and though it was thrown into vibrations when the stertor was strongest, it was 
evident that the cause of the sound was more deeply placed. I also found that, 
although firm traction upon the tongue abolished the obstruction and the stertor, 
it did not appear to produce the slightest change in the position of the base 
of the tongue ; nor did it move the os hyoides upon the thyroid cartilage, as 
examined from without. Hence I was led to conclude that the beneficial effect 
of this procedure could not be explained mechanically, but must be developed 
in a reflex manner through the medium of the nervous system. The fact that, 
when sensation is perfect, some degree of pain is caused in the process, implying 
an irritation of the nerves, was in favour of this view ; while the general abolition 
of reflex action by chloroform did not seem strongly opposed to it, considering 
that the reflex respiratory movements, including those of the glottis, go on in 
a person under the influence of chloroform. 
For further elucidation of the matter I had recourse to the laryngoscope ; 
and, after a little patience, found no difficulty in inspecting my own vocal ap- 
paratus without employing any depressor of the tongue, using simply the small 
oblique long-handled speculum and a common mirror in bright sunlight. I then 
ascertained that the true laryngeal stertor results from the vibration of the 
portions of mucous membrane surmounting the apices of the arytaenoid cartilages, 
i.e. the posterior parts of the arytaeno-epiglottidean folds (thick and pulpy in 
the dead body, but much more so when their vessels are full of blood), which are 
carried forwards to touch the base of the epiglottis during the stertorous breath- 
ing, and are placed in still closer apposition with it when the obstruction becomes 
complete. Having one hand at liberty, I was able to observe the effect of 
drawing forward the tongue under these circumstances, and I saw that firm 
traction induced the obstructing portions of mucous membrane in contact with 
the epiglottis to retire from it for about an eighth of an inch, so as to allow free 
passage for the air, while the epiglottis itself was not moved forwards in the 
slightest degree. 
* While the true laryngeal stertor was thus produced and thus removed, a sort of spurious snoring 
might be made by approximation of the vocal cords; but this spurious stertor was, like the voice, 
quite unaffected by drawing out the tongue. These observations were made on September 21 of the 
present year (1861). I find that there are four ways in which the passage through the larynx may be 
closed. First, the folding back of the epiglottis over the opening into the pharynx, as is generally 
believed to take place in swallowing, and may be demonstrated by arresting an act of deglutition in 
its progress, and insinuating the finger between the tongue and the roof of the mouth to the epiglottis, 
which is then felt to be turned backwards, and to return to its usual position as the act of deglutition 
is finished. Secondly, an approximation of the szdes of the superior orifice of the larynx, in which the 
epiglottis is directed forwards, but folded longitudinally, so that its edges are in contact with one 
another while the arytaeno-epiglottidean folds are also in lateral apposition. [Note written in April 
1908: This fact was observed in the retching caused by the application of a solution of nitrate of silver 
LISTER I L 
