230 
are received into the principal branches. These 
latter pass upwards in front of the transverse 
vein, to empty themselves on the left side into 
the termination of the thoracic duct; on the 
right, into the right lymphatic trunk, or they 
join the large veins separately, close to the en- 
trance of the two trunks of the system. 
The lymphatics of the lungs are of large 
size, and are divided, as in other parts of 
the body, into a superficial and deep-seated 
set. The latter accompany the ramifications 
of the bloodvessels and air-tubes throughout 
the texture of the organ, and communicate at 
various points with the superficial vessels. The 
principal branches escape from the lung at its 
root, where they are joined by the superficial 
vessels, and pass with them through the large 
bronchial glands. The superficial lymphatics 
of the lung are larger than those of any other 
viscus; they are situated in the interlobular 
fissures immediately under the pleura, and are 
injected with greater facility than the lymphatics 
of other parts of the body; their principal 
branches pass from the surface of the lung 
towards the inner edge and root of the organ, 
where they unite with the deep-seated ves- 
sels, and pass with them through the bron- 
chial glands. The vasa efferentia of these 
glands having communicated with the glands 
in the posterior mediastinum pass upwards on 
the trachea, where they meet with other glands 
with which they interchange branches; having 
entered the cervical region with the trachea, 
they unite freely with other lymphatics, espe- 
cially with those of the thyroid gland, and 
ultimately terminate, on the left side, in the 
thoracic duct; on the right, in the right lym- 
phatic trunk, or separately in the large veins. 
The lymphatics of the heart are neither large 
nor numerous; they proceed both from the sub- 
stance and from the surface of the organ ac- 
companying the principal bloodvessels; their 
appropriate glands are chiefly situated on the 
ascending thoracic aorta and trunk of the pul- 
monary artery; where these vessels are covered 
by the pericardium, they ascend in front of the 
arch of the aorta, pass between the sternum 
and transverse veins, communicate freely with 
the large vessels of the anterior mediastinum, 
and terminate with them on either side in the 
trunks of the system, the greater number, 
however, passing on the left sides to the tho- 
racic duct. 
The deep-seated lymphatics of the upper ex- 
tremity successively accompany the digital arte- 
ries, the superficial and deep palmar arches, 
the radial, ulnar, and interosseous arteries. At 
least two lymphatic vessels accompany each ar- 
tery; they communicate by short transverse 
branches with each other, and also at different 
sara with the superficial lymphatics. At the 
nd of the elbows they unite into three or four 
vessels which pass up the arm with the bra- 
chial artery to gain the axillary glands, into 
which they empty themselves. The small 
glands which not unfrequently may be found 
accompanying the brachial artery, and even, 
but more rarely, the ulnar or radial vessels do 
not generally intercept the deep lymphatic 
LYMPHATIC AND LACTEAL SYSTEM. 
Fig. 57. 
Superficial lymphatics of the 
( After Mascagni. 
a, a, Commencing lymphatic vessels ascend 
in the forearm with branches of the median vi 
b, c, d, The continuations of the vessels simi 
marked in the former woodcut. 
e, A vessel passing from the posterior to the ai 
terior surface of the arm over its outer edge. 
Ff, Branches of the basilic vein. 7 
» Cephalic vein. 
z Axillary glands. 
i, Two small glands situated above the int 
condyle. 
vessels, but the latter rather receive the eff 
vessels from these glands, they having collectet 
their afferent vessels from the surrounding tex- 
tures. 
