A STUDY OF THE CIRCULATION OF BLOOD 153 



relax in the organs that are active. It is manifestly impos- 

 sible to have an increased supply of blood in the organs of 

 digestion in the muscles, and in the brain all at the same 

 time. This is the reason why it is unhygienic for an adult 

 to exercise violently or to carry on any considerable degree 

 of mental activity immediately after eating. Persistence in 

 violating this rule usually results in attacks of indigestion. 



An important advantage of proper methods of exercise 

 comes from the fact that the blood is thus pushed onward 

 through the veins and the lymph through the lymphatics. 

 Most of the effect of the pulse beat is lost before the blood 

 reaches the capillaries, and much of the force exerted on the 

 veins and the lymphatics comes from the pressure of the 

 overlying muscles. The valves in these tubes prevent a back- 

 ward flow. Hence the blood and lymph are constantly 

 pushed on toward the heart by the muscular pressure upon 

 the veins and lymphatics, a pressure which is increased by 

 exercise. 



Treatment of Cuts and Bruises. One can tell when an artery 

 has been cut by the fact that blood comes out in spurts. 

 Since the blood is on its way from the heart, the flow can be 

 stopped or lessened in this kind of accident by applying 

 pressure on the side of the wound nearest the heart. Thus 

 if the finger is cut deeply and the blood jets forth, a strong 

 cord or a handkerchief should be tied loosely about the wrist, 

 and a pencil or piece of wood should be placed beneath, and 

 then the bandage should be twisted until the blood flow is 

 stopped by the pressure. When blood flows evenly from a 

 wound, it is an indication that a vein has been cut, and the 

 pressure should be applied in a similar way on the side away 

 from the heart. 



Bleeding from the nose can usually be stopped by hold- 

 ing the head erect, and by applying cold water to the bridge 

 of the nose or to the back of the neck. 



In case of a cut or of a bruise in which the skin is broken, 

 the wound should be cleansed as quickly as possible with 



