ANATOMY. 
pass along the right side of this process; 
and the part in which they are situated is 
called the capsula Glissoni. Under the edge 
of this part is an opening, leading to the 
bag of the great omentum, and called the 
foramen epiploicum. 
GALL-BLADDER AND BILIARY DUCTS. 
The gall-bladder is a membranous bag, 
serving as a reservoir for the bile. Its shape 
is that of a pear, being broader at one end, 
and diminishing conically towards the oppo- 
site extremity. The broad end is called 
the fundus ; and the smaller part the neck 
of the viscus. Its average capacity may be 
about one ounce. It is firmly bound to the 
surface of the liver by peritoneum. Its inner 
surface is elegantly reticulated, and furnishes 
a viscid mucus that mingles with the bile. 
The hepatic duct is continued in a straight 
course from the liver to the duodenum, in 
which it opens. It passes, however, in an 
oblique manner, between the coats of the 
intestine, before opening into its cavity. 
Hence the contents of the intestine cannot 
enter the duct; and the more fully the in- 
testine is distended, the more completely is 
this prevented by the compression of the 
duct between the intestinal tunics. The 
neck of the gall-bladder is gradually con- 
tracted into a small tube, called the cystic 
duct, which joins the hepatic at an acute 
angle, after first running parallel with it. 
The remainder of the hepatic duct after the 
junction with the cystic, is often called the 
ductus communis choledochus. The surface 
of the cystic duct, as well as that of the 
neck of the gall-bladder, has numerous small 
folds of the internal membrane, which must 
retard and obstruct the course of the bile. 
Pancreas — Is a gland of the conglome- 
rate kind; that is, composed of numerous 
minute portions, united by cellular sub- 
stance. It is connected by one end to the 
commencement of the duodenum, and ex- 
tends across the vertebra;, behind the lesser 
arch of the stomach, to the spleen. Its 
length is about six inches ; its breadth one 
and a half ; and its thickness half an inch. 
Each of the small molecules which com- 
pose this gland, has an excretory duct ; these 
unite together into larger and larger trunks, 
and the main tube of all runs along the 
centre of the gland, and joins the ductus 
communis choledochus just before that duct 
opens into the duodenum, 
Spleen — This part, which in common lan- 
guage is called the milt, is a soft and livid 
mass interposed between the great end of 
VOL. I. 
the stomach and the diaphragm. It weighs 
about six or seven ounces. It consists of a 
congeries of cells filled with blood ; as the 
arteries and veins of the organ communicate 
with them. It is closely connected to the 
great end of the stomach by vascular ra- 
mifications, which the splenic vessels send 
to the stomach. It has a concave and a con- 
vex surface ; an anterior and posterior ex- 
tremity ; and an external peritoneal cover- 
ing. 
ORGANS OF RESPIRATION. 
As these are contained in the cavity of 
the thorax, we shall consider the subject in 
the form of a description of that cavity and 
its contents. 
The cavity of the thorax is the space in- 
cluded by the dorsal vertebra; behind, by 
the ribs with their cartilages, the sternum, 
and intercostal muscles, at the sides and fore- 
part ; and by the diaphragm below. This 
cavity is lined by a membrane called the 
pleura, which has a smooth internal sur- 
face constantly moistened by a serous ex- 
halation. 
The cavity of the chest contains two dis- 
tinct membranous bags, called the right and 
left bags of the pleura ; each of these holds 
the lung of its own side, aucfis entirely sepa- 
rated from the opposite one. The pleura not 
only forms a bag which holds the lung, but 
is also reflected over the surface of the vis- 
cus, bestowing on it a smooth exterior in- 
vestment. This is called the pleura pulmo-, 
nalis, to distinguish it from the other, which 
is named pleura costalis. 
If the cartilages of the ribs be divided on 
one side of the chest, the corresponding 
bag of the pleura will be opened ; and it 
will then appear, that this is separated from 
the opposite one by a partition, which ex- 
tends from the sternum in front to the ver- 
tebrae behind, and is known by the name 
of mediastinum. The pleurae may be com- 
pared to two bladders placed laterally with 
respect to each other, but adhering only 
partially, and separated by various inter- 
vening bodies. Thus, the heart and ad- 
joining large blood-vessels, the oesophagus 
and the division of the trachea into the two 
bronchi, are placed between the two"pleuraj. 
The mediastinum then is the space included 
between the opposed surfaces of the two 
bags of the pleura*, and containing the parts 
above mentioned. The name of anterior 
mediastinum is applied to a small interval 
left between the two pleurae, just behind 
the sternum, and occupied only by a loose 
cellular texture. The posterior mediasti- 
O 
