612 A N A T 
Hence expiration is performed more eafilv and quickly than 
inspiration; and hence it is the laft aCtion •; f dying people. 
The inconveniences produced by expiration, excite new 
efforts for repeating the refpiration ; becaufe the collapfed 
veilels of the lungs refill the blood expelled from the right 
ventricle of the heart. Hence the caufe of death in thofe 
animals which expire in veflTels exhaufied of air. For 
their lungs, being void of air, become denfe, folid, and 
’heavier than water, whence they are rendered impervious 
to the blood. Of the fame kind is the death of th@fe who 
are killed by lightning, and, perhaps, by the noxious va¬ 
pours of caverns. How admirable are the ftruCture and 
-rneclranifm in thefe organs of refpiration! The uneafy 
fenfations of a too long continued expiration, which arife 
from, hindrances of the blood’s pallage through the lungs, 
excite into aCtion the powers of infpiration, whereby the 
blood’s pallage through the lungs is rendered again more 
free and eafy; and, vice verfa, the unealinefs proceeding 
from a too long continued infpiration excite the powers 
of expiration. 
Refpiration feems Somehow to agree with the puliation 
of the heart, there being ordinarily three or four pulfes to 
one refpiration. And, if a greater quantity of blood is 
Sent to the heart in a given time, the numbers both of the 
pulfe and refpiration are increafed. This is the reafon of 
the panting or Short breathing, after exercife, or any con¬ 
siderable motion, which increafes the return of the blood 
to the heart. If the blood meets with a refinance in the 
lungs, fo that it cannot pafs freely from the right into the 
left ventricle of the heart; then the refpiration is increa¬ 
fed, both in quicknefs and magnitude, in order to forward 
its cotirfe. And this is the caufe of Sighing, yawning, 
and panting; of which the firlt is a deep infpiration ; the 
Second a flow and very great one; and the third a frequent 
and imperfect one. The number of refpirations, how¬ 
ever, does not always increafe with the pulfe, as we fee in 
thofe fevers where the lungs are not affected. The mu¬ 
cus, which lines the fenlible membranes of the air-velfcls 
in the lungs, may become troublefome, both by its quan¬ 
tity and acrimony; it has been known to caufe even fuffo- 
cation in a dropfy of the lungs. Its quantity, adhefion, 
or acrimony, therefore, excite a cough ; which operation, 
caufed by an irritation of the organs of refpiration, is per¬ 
formed by alternate large infpirations, Succeeded by large 
and quick expirations, together with Sudden (hocks of the 
abdominal mufcles; and by thefe means the mucus, and 
Sometimes calculous matters, are expelled from the lungs. 
Laughter differs from coughing in its caufe, which re- 
Sides commonly in the mind, or at lead conlillsin a certain 
titillation of Some of the cutaneous nerves; and alfo its 
aCtion, which is one large infpiration Succeeded by Several 
imperfect quick expirations through the contracted glottis, 
the lungs being never totally evacuated of air. Hence 
laughter, in a moderate degree, conduces to health; be¬ 
cause, inltead of one full infpiration, many fiiort infpira¬ 
tions and expirations happen, and thus the concuflion is 
greater. Hence its danger of flagnating the blood ; be- 
caul'e the expiration is not full or entire, and the blood is 
admitted into the pulmonary artery without being Suffered 
to pafs through it. Weeping begins with a great infpira¬ 
tion, after which follow ihort alternate infpirations and 
expirations; and it is finiflied with a deep expiration, that 
is immediately joined by a large infpiration. Hence it 
has nearly the fame good and bad effects; and, when mo¬ 
derate, it conduces to relieve the anguifb arifing from grief. 
An hiccup is a very great, Sonorous, and hidden, inspira¬ 
tion. Sneezing confifts of one large or deep infpiration, 
which is followed immediately with a powerful and Sudden 
expiration; it evacuates with great violence any acrid or 
other fubllance irritating the nollrils. 
Some of the Secondary ufes of refpiration are to com- 
prefs the abdominal vifeera, fo that the ftomach, intef- 
tines, gall-bladder, receptacle of the chyle, bladder, in- 
teftinum reCtum, and the womb itfelf, may discharge their 
contents; that the aliments may be triturated or diii'olved, 
O M Y. 
and the blood urged through the fluggilh veilels of the 
liver, fp!een, and mefentery. Refpiration excites a kind 
of flux and reflux in the blood, fo that it is alternately 
prelfed back towards the extremities of the veins, and a 
little after is propelled towards the heart by an accelerated 
velocity. Moreover, infpiration Serves to convey odours 
along with the air to the organ of Smelling; and is alfo 
the principal means by which a new-born infant is enabled 
to perform the operation of fucking. 
OF THE ABDOMEN. 
The cavity of the abdomen is of an irregularly-Oval fi¬ 
gure, but ftiil Symmetrical. On the fore-lide it is uni¬ 
formly arched or oval, and its greatell capacity is even with 
the navel and neared part of the hypogaftrium. On the 
upper fide it is bounded by a portion of a vault, very much 
inclined. On the back-fide it is in a manner divided into 
two cavities by the jutting out of the vertebrae of the loins. 
On the lower-fide it contracts gradually all the way to the 
edge of the pelvis ; and from thence expands again as far 
as the os coccygis, and tubercles of the ifehium, termina¬ 
ting in the Void fpace between thefe three parts. 
Having carefully removed the mufcles of the abdomen, 
the firlt thing we difeover is a very conliderable membra¬ 
nous covering, which adheres immediately to the inner 
Surface of themufeuli tranfverfi, and of all the other parts 
of this cavity, and involves and invells all the vifeera, as 
in a kind of bag. This membrane is named peritonxum, 
from a Greek ivord, which Signifies to be Spread around. 
The peritonaeum, in general, is a membrane of a clofe 
texture, and yet very limber, and capable of a very great 
extenfion; after which it can recover itfelf, and be con- 
trailed to its ordinary Size, as we fee in pregnancy, drop- 
lies, corpulency, and repletion. The ufes of the perito¬ 
naeum, in general, are, to line the cavity of the abdomen, 
to invell the vifeera contained in that cavity as in a com¬ 
mon bag, to Supply them v. nh particular coats, and to 
form productions, ligaments, connections, folds, vaginae, 
&c. A fine fluid tranfudes through the whole internal 
Surface of the peritonaeum, which prevents the inconve¬ 
niences that might arife from the continual frictions and 
motions to which the vifeera of the abdomen are expofed, 
either naturally or by external impulfes. 
The ventriculus or (lomach, is a great bag or refervoir, 
fituated partly in the left hypochondrium, and partly in 
the epigaftrium. The figure of the llomach is oblong, 
incurvated, large, and capacious, at one end, and fma.l 
and contracted at the other. We fee this figure mod ev : - 
dently when the llomach is moderately filled with air, or 
with any other fluid. It has two openings, called the 
orifices'of thefomack ; one between the great extremity and 
the Small curvature, the other at the end of the Small or 
contracted extremity. The firlt opening is a continuation 
of the cefophagus; the other joins the intellinal canal, 
and is called the pylorus. The ftomach is cotnpofed of 
Several tunicae or coats. Thefe coats are commonly reckoned 
to be four in number ; the outer or common, the flelhy or 
mufcular, the nervous or aponeurotic, and the villous or 
inner coat; and they are afterwards Subdivided Several 
w ays. The firlt or outermoft coat is limply membranous, 
being one of the internal productions of the peritonaeum. 
The Second or mufcular coat is made up of Several planes 
of fibres, which may all be reduced to two; one exter¬ 
nal, the other internal. The external coat is longitudinal, 
though, in different refpeCts, following nearly the direc¬ 
tion of the curvatures and convexities of the ftomach; and 
the internal plane is tranfverfely circular. The third coat, 
commonly called tunica nervofa , but'properly tunica cellulofa , 
is compofed of capillary velfels and nerves, with a very 
large proportion of cellular fubftance. The fourth coat of 
the ftomach has been termed by Fallopius tunica villofa , 
becaufe, when it fwims in clear water, foiffething is feen 
in it like the pile of velvet. The ancient called it tu¬ 
nica fungofa ; and perhaps this name agrees belt with its 
true ftruCture, 
The 
