294 HUMAN PHYSIOLOGY CHAP. 



The most effective means of preventing and eradicat- 

 ing this loathsome disease is vaccination, which produces 

 a very mild form of the disease that makes the person 

 immune for a number of years. Vaccination has proved 

 a great blessing to mankind, for it has saved millions of 

 lives from this deadly scourge. 



Chicken pox is a mild, "air-borne" disease in which 

 appear skin eruptions that sometimes form small scabs. 

 It is contagious and may be transmitted until the scabs 

 have all disappeared. Small scars or pits are sometimes 

 left that disfigure the face. 



204. Mumps. This is a very contagious disease of 

 childhood and youth, in which the salivary gland below 

 the ear becomes infected and very much enlarged. It 

 is probably caused by bacteria, although we are not 

 certain of that. Mumps is not very painful and seldom 

 proves fatal. The only means of preventing the dis- 

 ease is complete isolation for about three weeks. 



205. Whooping Cough. This is a contagious disease 

 of childhood. It is accompanied by a peculiar spasmodic 

 cough, followed by a whoop (from which it gets its name) 

 as the breath is inhaled. The lungs are invaded by the 

 germs and may become so affected as to cause death. 

 The disease may be communicated from one person to 

 another through the breath and matter thrown off in 

 coughing, but it is probably not carried by a third 

 person nor in clothing. It is contagious from the first 

 until the cough and whoop have entirely ceased, which 

 usually continue for a period of from three to six weeks. 

 During this time the patient should remain isolated. 



