CONTAGIOUS DISEASES 299 



warned not to attend church or other public gatherings, 

 and, as far as possible, not to mingle with others during 

 the period of danger. In cases of smallpox, scarlet fever, 

 and diphtheria, placards are placed on the patients' 

 houses to warn the public that the dangerous disease 

 is within. Such cards must not be removed until 

 the health officer or one of his assistants is satisfied 

 that there is no longer danger of contagion. These 

 officers are also expected to see that there is proper 

 disinfection of the room and premises afterward. 



While some people have had smallpox, scarlet fever, 

 or measles two or three times, having had any one 

 of them once seems, as a rule, to make one immune 

 from a second attack of the same disease. It is well 

 known that we can protect ourselves from smallpox 

 by vaccination. In many cities, children must be 

 vaccinated before they enter school, and again in four 

 or five years. It is also wise to be revaccinated later 

 in life whenever one is where a smallpox epidemic 

 prevails. 



Some children and parents try to evade vaccination. 

 This seems a very foolish thing to do, because results 

 show that its benefits have been great. In the year 

 1900, the deaths in the United States from smallpox, 

 according to the census returns, numbered three 

 thousand four hundred eighty-four. If the rate had 

 equalled that of England and Wales before the dis- 

 covery of vaccination, the number would have been 

 two hundred sixteen thousand. In the latter two 



