HEART AND BLOOD VESSELS 
455 
ways. (1) There is no special organ for forcing the lymph 
along, the circulation depending mainly upon the movement 
of the muscles. (2) The lymphatic vessels are imperfect in 
the beginning, being only irregular spaces. (3) The lymph 
contains no red corpuscles and only a few white corpuscles. 
Cuts. — Since every part of the body inside the skin is 
traversed by blood vessels, we 
cannot injure any part without 
breaking some blood vessels. A 
small cut causes the blood to flow 
only from capillaries, and it flows 
slowly and in small quantities. 
If a vein be cut, the blood will be 
dark in color, and will flow in 
larger quantities, but steadily. 
A severed artery sends out bright 
red blood in waves corresponding 
to the beat of the heart. To stop 
the flow of blood from a vein, 
compress the vein beyond the 
cut; from an artery compress the 
artery between the cut and the 
heart. In either case remain quiet 
to aid the blood to form a clot. 
Exercise. — The object of a cir¬ 
culatory system and of a circula¬ 
tory fluid is to supply every cell 
in the body with food and to 
carry away the waste. The more 
active the process of circulation, the more perfectly is this 
object accomplished. It is the common experience that the 
heart beats more rapidly, the lungs work harder, and the 
body becomes warm after a few minutes of vigorous exer¬ 
cise. These changes have a decidedly beneficial effect upon 
building up the body and removing the wastes. 
Figure 405. — Main Arteries 
of Man. 
Compare with Figure 404. 
