SYSTEMATIC SYNTHESIS OF TISSUES INTO ORGANS. 329 



944. THE ARRANGEMENT AND CONSTRUCTION OF THE 

 ARTERIES AFFORD every facility for the rapid flow of 

 Blood in a concentrated volume, buried where its warm 

 current will be least exposed to loss of heat, and least 

 likely to be tapped by superficial injuries ; and even 

 when the arteries are severed their contraction diminish- _ 

 es their calibre very much, and if the injury is such as 

 to cause the artery to be extended, as is usually the 

 case, it is closed by that very action. 



945. WHEN AN ARTERY, THOUGH NOT VERY LARGE, 

 is CUT, and not closed by the effect of the injury, its 

 structure and use cause the Blood to flow in jets, or 

 pulses, with serious rapidity, and life will be lost, unless 

 the flow is speedily stopped by forcible compression. 



946. Remark. THE FACT MENTIONED IN ^[ 945 SHOWS the impor- 

 tance of having every person understand the position of the large arte- 

 ries in the thigh and arm, and know how to compress them at that point, 

 for that cuts off the flow below. Forcible pressure may be made with 

 the thumb over the artery upon the hip-bone, or with the fingers over 

 the artery in the arm ; or a bandage, handkerchief, or cord, can be drawn 

 tightly around the limb or twisted tightly by the aid of a stick- inserted 

 beneath it, loosely tied around the limb ; a knot may be made in the 

 bandage and placed over the artery, or a smooth stone, a chip, half an 

 inch or more thick, or a few pieces of coin, may be used to produce 

 pressure directly on the artery. The best bandage is an elastic one, like 

 an elastic suspender, or ladies' belt, wound tightly several tunes around, 

 each turn of course increasing the pressure. It is not best to stop the en- 

 tire flow of Blood ; it should only be well checked, since Blood is essential 

 to the vitality of the parts immediately around the wounded part, and a 

 little blood had better be lost, than not to have any received below the point 

 of pressure upon the artery. (See Ap. M.) 



947. THE ARTERIES OPEN INTO the capillaries; their 

 basement membrane, like that of the veins, is continu- 

 ous with the walls of the capillaries. 



948. THE USE OF THE ARTERIES is not only to lead 

 the Blood from the Heart to the capillaries, but to assist 

 in forcing it along. 



944. What does ? 945. What effect ? 946. What does ? Should blood 

 be entirely checked ? 94T. what ? 948. What is ? 



