94 STOPPING OF HEMORRHAGE. 



phere ; some, to the vacuum produced by the dilatation 

 of the venous auricle ; some, to muscular action ; and 

 some to the sole and unassisted action of the veins 

 themselves. Perhaps if the truth were known, each of 

 these agents would be found to have a share in produ- 

 cing the effect in question. 



The knowledge of the course of the blood has been 

 of signal service to surgeons, as well as physicians. 

 The older surgeons, when they cut off a limb, had no 

 means of arresting the flow of blood from the divided 

 vessels, but that of searing the stump with a hot iron. 

 This answered the purpose for a day or two, but then 

 it generally broke out again, so that the surgeon was kept 

 in constant dread of a secondary hemorrhage which 

 would destroy his patient's life, before his assistance 

 could be given. Now, the surgeon ties up the vessels 

 with a piece of silk, and goes away without any appre- 

 hension of being called again to see his patient floating 

 in his own blood. Besides, if the blood should gush 

 out again, it can be instantly checked without waiting 

 for the surgeon to come and tie up the vessels ; for 

 knowing the course of the blood, all we have to do is to 

 press upon the artery and the flow of blood stops at 

 once. 



Emily. And this is something which would be ex- 

 ceedingly useful to other people as well as surgeons to 

 know, for wounds of the vessels sometimes would de- 

 stroy a person, before the surgeon could arrive and stop 

 the bleeding. But, Dr. B., how is every body to know 

 the situation of the artery which is to be compressed ? 



Dr. B. If it is not so superficial that it can be felt, 

 as it is in the wrist, a bandage, or a common handker- 

 chief tied tight round the limb, will effectually stop the 

 flow of the blood. Recollect however, that it is not in- 

 different on which side of the wound you use the com- 

 pression. 



Emily. That would depend on the kind of vessel. 

 If an artery were wounded, the compression must be 



