THE LYMPHATIC SYSTEM gI 
may be seen by ordinary dissection, the structures which appear in 
this way in being the lymph glands, or lymph nodes, centres of cell 
formation, occuring in the course of the conducting vessels. These 
as superficial structures are found either singly, as in the head and 
neck, or more or less grouped, as in the axillary and inguinal spaces. 
As deep structures they are conspicuous in the intestinal mesen- 
teries, and in the walls of the digestive tube, occuring in the latter 
chiefly as continuous masses of lymph follicles, as, for example, 
in the walls of the sacculus rotundus, the vermiform process, or the 
tonsil; or, again, as aggregated lymph follicles (Peyer's patches) 
at various points in the intestinal wall. 
The conducting portion of the 
system comprises an _ extensive 
series of canals, beginning as lym- 
phatic capillaries in peripheral 
organs, and ending as lymphatic 
trunks which empty into the great 
veins. The lymphatic trunks of 
the anterior portion of the body are 
designated from their association 
with the corresponding veins as 
jugular and subclavian. They 
enter the venous system on either 
side at the point of junction of the 
internal and external jugular veins — semaie i SR 
: urinary bladder; cc, crura clitoridis; cp, 
ono the common jugular and sub- “Gira penis: hdd, ductus: deferens.” ep. 
clavian (Fig. 82). Shae Ree ay Sie asa: a 
Wikier lycnphaticuvessela ot! the Wa ceminalvescel yetvestinulum. 
posterior portion of the body, 
including the intestine, unite to form a common canal, the thoracic 
duct. The latter lies for the most part between the aorta and the 
vertebral column, and traverses the thorax in this position to enter 
the venous system at the same point as the jugular and subclavian 
trunks of the left side. 
The lymphatic capillaries are terminal, absorptive vessels, 
differing from blood capillaries both in the character of their walls 
and in their relations to other portions of the system, since they 
are not interposed as in the vascular system between vessels of a 
larger order. The lymphatic vessels connecting the capillaries 

