INCUBATION PERIOD OF DISEASE 



473 



cause the symptoms of the disease. This period, between the 

 time when the germs enter the body and the time the symptoms of 

 disease appear, is called the incubation period. Since this period 



a neighbor- and 

 playmate Gpn 22 

 quarantined 

 for- measles 



a .school chum, 

 not at par t>^ 

 quarantined 

 vi tte rr}easksAprr20 



party held" Apn 8 

 at Valentine borne. 

 AprrloJanetVthe 

 l205tess" developed 

 measles 



Apr: 21 Dorothy 

 5. quarantined 

 with rrceasles- 

 gaest at party 



Patty and £ lien 5. 



i/ith measles 



Apn24"MaryTT 

 quarantined 

 >xdth measles - 

 guest at party 



Two days after her party Janet developed measles. Since she was not ill with the disease 

 at the time of the party, how do you account for the other cases which developed? 



varies for different diseases, the period of quarantine also varies, 

 as seven days for scarlet fever, fourteen days for whooping cough, 

 twenty-one days for chicken pox. If, after one has been exposed 

 to an infectious disease, no symptoms develop within the time of 

 the recognized incubation period, it is safe to assume that he will 

 not get the disease. 



Practical Exercise 11. Study the diagram. How have similar cases worked 

 out in your own school? Diagram them. 



Why is it necessary for protection of others to know the incubation period of 

 a disease? 



Practical Exercise 12. Why should persons ill with an infectious disease 

 be isolated until they are well? What methods has the Board of Health for 

 warning strangers of the presence of the disease in a home ? 



What is the reason for quarantine and by what should it be followed to be 

 effective ? Why is there a quarantine station at the entrance of San Francisco, 

 Boston, or New York harbor? Why is it of particular value there? 



Practical Exercise 13. What do we mean by disinfection? What are the 

 rules of your local Board of Health in regard to disinfection. 



What should be done to the body, clothing, and hair of a person who has 

 been ill with an infectious disease before he is allowed to go among well persons 

 again? Why is this necessary? 



Can a person have the germs of a disease in the body and still not show 

 symptoms of the disease? How might such a person be a danger to others? 



