SUGGESTIONS FOR LABORATORY WORK 617 



pressing the ruptured blood vessel on the side of the injury from 

 which blood comes. 



Arterial bleeding can be distinguished from venous by the 

 brighter color of the blood and by the fact that the blood escapes 

 in jets. When bleeding is from veins the flow is steady and the 

 blood is dark. 



Veins which are likely to be injured are on the surface. A band- 

 age tied tightly around the arm or leg in proper position relative 

 to the injury usually suffices to check venous bleeding. Select a 

 point on the arm as a possible seat of injury. Adjust a bandage 

 in such a position as to cut off venous flow to the chosen point. 

 Show on a diagram the position of injury point and of bandage. 

 Indicate direction of venous flow by arrows. 



Arteries are deep seated through most of their course, and blood 

 pressure within them is high. To check arterial bleeding strong 

 pressure on properly selected points is necessary. Expose the 

 entire arm. Find a point near the upper and inner margin of the 

 biceps muscle where the pulse can be felt. Strong pressure on 

 this point if properly applied will check arterial bleeding below. 

 For a more permanent check make a hard knot the size of an 

 egg in the middle of a handkerchief. Tie firmly around the arm 

 just above the elbow with the knot in front. Bend the forearm 

 so that it presses hard against the knot. If the procedure is suc- 

 cessful the pulse at the wrist disappears. Another method is to 

 make a hard knot of cloth the size of a fist. A round stone or other 

 hard substance may be used. Push it hard into the arm pit. 

 Bring the elbow straight down and hold it firmly against the side. 

 The success of the procedure should be tested by observing whether 

 the pulse at the wrist disappears. (For the control of bleeding in 

 other regions than the arm see Dulles: Accidents and Emergencies, 

 Philadelphia, 1899.) 



The Effect of Muscular Movement on Venous Flow. Tie a cloth 

 tightly about the arm at the elbow. Note the rate at which the 

 superficial veins become congested. Loosen the cloth until the 

 veins return to normal. Replace the cloth about the arm and 

 close and open the hand several times. 



Compare the rate of venous congestion with that seen in the 

 quiet arm. 



