DEGLUTITION. 
the palate. = phyfiologifls have flated, that the food, 
by its preffure on the epiglottis, deprefles that organ more 
completely, ae applies it more clofcly over the opening ; 
and hi appears probable enough refpeéting the more folid 
maffes: but if we confider a a drop of fluid, ewe in- 
adequate to produce any efl on the epigiottis, is {wal- 
lowed jut as well as the cane aes of alinicnt, we thall 
not sae much influence to this caufe 
t is obvious, from ve pieces account, that refpira- 
tion ait experience a temporary interruption, while the 
food is paffing over the Gee Hence if a perfon im- 
prudently laugh, or attempt to {peak, while he is fwallow- 
ing, the efcape of air from the lungs, which is necefflary in 
both cafes, lifts up the epiglortis, and gives admiflion to ae 
food, which is then not inaptly ftated in common language 
f {Iced into 
a : tr 
reltored to its former pofition; the glottis becomes again 
open for refpiration, which had fuffered a merely momentary 
interruption. annot conclude this part of the fubjeét 
without making one obfervation, which will naturally tug- 
geft itfelf to the reflecting mind, on the sia of the 
parts whofe funGions we-are now deferibing. We fee that 
nature has deflined the fame organ to the performance of 
two important proceffes:; that the mungs pa their mupply 
of air through the pha arynx, a and that tube con 
our food to the ftomach ; aifo, that ie cour fe “of the aliment 
filts between life aud refpiration; that the interruption of 
this fundion, even fora very fhort time, produces inevitable 
death. Now we can fee very clearly, that if the glottis 
were left open when we {wallow, alee wou ss be a 
probable confequence of the firlt — m the entrance of 
ee food into the trachea the Sele of the alos 
not been entrufted to “the gree of any of thofe means, 
heh depend on the exertions of the will, which are always 
irregular and uncertain, and influenced by numerous cir- 
any liable to change, from alterations in the bodily 
mental ftate of individuals ; but it ie lows as a neceffary 
ertain motions of the 
organs, and wiil take place in the fea as well as in the liv- 
ing fubje&t. Further, the very fame condition of parts, ee 
produces the danger, brings with it the provifion a 
that danger. The rifle obtains only in the act of {wallow mee F 
and the elevation of the larynx; which is an effential part of 
the procefs of deglutition, clofes the glottis, and thereby 
i litad the rifk. 
From the connexion fubfifting between the larynx and 
phar have already va ained, = latter part is 
elevated together with the forme the fame time 
dilated by the ftylo- ‘oun aa mae as ne ie is rather 
ater fpace i is - between it and t 
nx. 
r{t was a ieae up againft the 
the nfl, is again deprefled, as foon as 
mus ; and its depreffion affiis in 
promoting the defcent of the food intothe pharynx. ‘This 
motion is performed by the palato-gloffus and palato-pha- 
ryngeus, which bring the velum palati in contact with the 
back of the tongue, ‘and thereby cut off the return of the 
oone 
ntraéts, and the 
the fpace between the tongue and ha ria? is deftroyed by 
the eee oe of the poltcrior part of the pharynx to the 
otion feems to arife from the Irritation pro- 
touyue. 
duced by the pierce of the food ; for we cannot a fx ale 
owing whatever has entered the fauces. T ne action of the fu. 
a conflriétor mufcle draws the upper part of the pha- 
ie aaeio® the foft palate, and thereby here ~ food, 
into that cavity. The fucceflive contractions of the middle 
and lower conitri€tors now urge the food through the pha- 
rynx into the efophagus; the arytenoidei probably clofiag 
the rima_glottidis while the food pafles behind that part. 
The lar d to its natural pofition by the 
y its own e€ 
fes n 
azygus would bring ie the palate and uvula to their ufual 
condition, 
We fee, therefore, that the bufinefs cf oe requires 
the concurrence cf numerous parts, and t 
feveral motions, and becomes 
and difficult ftudy. 
weight, but is urged a dh the whole courfe by mufcular 
contraction. ence we may {walléw with the trunk in- 
ida 3 and in Saige canna the food paffes upwards to the 
ftom ek eee is deftroyed altogether by pas 
igee ace oe 
lowing of fluids can ht 
than that of folids: the contaé of ce fides of the pharynx 
and cefophagus prefents an obftacle which a mouthful of 
fluid is not capable of overcoming, and which requires a con- 
traction of the mufcles. Between the oppofing fides of the 
tube, and the contraGting fibres of the organ, fluids are col- 
leé&ted into a globular form, like the a folid fpecies of 
; as we may obferve in a horfe when drinking, where 
the paflage of the fluid in i. manner ie deferibed is very 
obvious. 
o 
The e/ophagus is a cylindrical mufculo-membranous tube, 
extending from the pharynx to the ftomach, and defigned to 
oe the food from the former to the eee of thefe or- 
gan 
ir defcends through the lower part of the neck, betwee 
the trachea and the vertebre ; being not exaatly behind, a 
rather to the left of that tube. 
pany with the trachea, bet the two bays of the pleura; 
e paffes ‘behind the left branches, and to the right ial ig = 
of the aorta; then, turring over the defce nding ai » Zoe 
Behe rahe left mufcle, and defcends : rough c pote 
mediattinum, ju in on of that part of the aoita which 
lies again{t the vertebre of the its ioe part it 
advances flightly forwards from the vertebral column, paff-s 
through the sala: eperture of the diaphragm, and termi- 
nates in the ftoma 
The connexions Sof the ee to the furrounding 
parts are formed by a loofe cellular 
dium, and bafe of the heart. It correfponds Lchind, in the 
Oo 2 nec 
