COMMON ACCIDENTS AND INJURIES 345 



495. Injuries to Blood Vessels. If the capillaries merely 

 are hurt the blood only oozes slowly ; a clot will soon be 

 formed and the healing process begun. If a vein is opened, 

 the blood flows in a steady stream and is of a dark purple 

 color. But when an artery is divided, the blood from it 

 is bright scarlet and comes in spurts, corresponding to the 

 heart beats. Bleeding from an 

 artery is the most dangerous and 

 the most difficult to check. That 

 from capillaries and small veins 

 will ordinarily check itself by 

 the formation of clots, but the 

 flow from an artery may be so 

 fast as to prevent clotting. A 

 doctor is usually needed, but no 

 time must be lost in waiting for 

 him. Strong pressure must be 

 at once applied upon the artery, 

 either in the cut or between the 

 cut and the heart. If the injury 

 is to a limb, a handkerchief or 

 other bandage may be tied (in a 

 knot that will not slip) around Fig. 139. Manner of com- 

 if alm^A fVia Tmrf tlia liarr! Vnnt pressing an artery with a 



rt, t- L Knot handkerchief and stick, 



placed over the artery, and a stick 



inserted under the bandage (Fig. 139). By twisting the 

 stick the knot may be pressed upon the artery hard enough 

 to stop the bleeding. A firm hand may be able to effect 

 the same object with the thumb and finger, changing from 

 place to place till the right spot is found. Or a strong 

 rubber band or tube may be stretched, wound round and 

 round the whole limb, and tied. 



A knowledge of the course of the principal arteries is 



