400 



APPLIED PHYSIOLOGY 



while the dead cells, or pus and plasma, run off in a continuous stream. 

 So bacteria hinder the repair of wounds, and prevent their edges from 

 growing together directly. Then the cut must slowly heal from its 

 bottom. When a wound begins to be tender and to discharge, it is 

 said that one has taken cold in it. Taking cold in a wound means 

 that bacteria are growing in it. Their toxins may poison the whole 

 body and produce a severe fever, which may cause death. Surgeons 

 now exclude bacteria from the wounds which they make. The white 

 blood cells then have nothing to do but repair the cut, and every part 

 of the wound heals at once. Healing applications do good mainly by 

 destroying germs which may come near the wound. 



704. Treatment of in- 

 flamed wounds. A 

 tender discharging 

 wound should be 

 cleaned with boiled 

 water, and covered with 

 a a clean antiseptic dress- 

 ing, to soak up the dis- 



The second stage of inflammation (X 200). charges and bacteria. 

 a white blood cells which have left the capillary. The dressings should 



be changed as soon as 

 they become full of 

 matter. Inflammation 



may be prevented by covering fresh wounds with clean 



dressings. 



When an abscess is forming, the heat of a poultice dilates the blood 

 vessels, and so hastens the softening process. Thus it "brings the 

 abscess to a head " and hastens the discharge of the pus. Since the pus 

 will form anyhow, it is always better to open the abscess and let out 

 the matter at once. This can be done without pain by using cocaine. 



705. Taking cold upon the lungs. When a mucous 

 membrane is injured, as by exposure to cold, there will 

 be the same changes in its blood tubes as in a wound 



b white blood cells which nearly block the 



capillary. 



c a few red blood cells which still circulate. 

 d wall of the capillary. 



