210 CIRCULATION 



strip of cloth and a stick. The toirrniquet is of course 

 only a temporarj^ measiu-e and is to be employed only as 

 an emergency remedy until the surgeon can treat the 

 wound. Surgeons usually close large wounds by tying the 

 ends of the cut blood vessels with clean catgut. Such 

 bindings are called ligatures. 



When the ends of a vein are cut they may grow together 

 again and thus circulation be restored tlirough the original 

 channel. Aitery ends, on the contrary, do not grow to- 

 gether but the ends close and the branches which are in 

 commimication above and below the cut enlarge and replace 

 the original channel. 



All cuts should be kept clean and free from bacteria. 

 Weak solutions of certain germicides can be obtained from 

 druggists and used to wash and protect the cut from these 

 dangerous visitors. Blood poisoning is one of the serious 

 results of neglect of these precautions. 



The healing of a cut or bruise will take place without 

 pain or inflammation if kept clean. 



Effect of alcohol upon the circulation. — The most 

 marked effect of small amounts of alcohol is the dilation of 

 the surface capillaries and their filling with blood. The 

 result is a sensation of -n-armth or glow due to the stimu- 

 lation of the siu-face heat nerves. Alcohol produces this 

 effect by its action on the nerve centers, which, in turn, 

 stimulate the vaso-dilator nerves of the arteries that supply 

 these capillaries, and not by any direct action upon the 

 blood vessels. 



In this case the sensation of warmth is deceitful, since 

 the bringing of the blood from deeper parts of the body to 

 the surface permits the escape of heat and a slight lower- 

 ing of the body temperature. 



