isolated from others until the period of incubation has passed 

 without any signs of the disease appearing. In the case of 

 chickenpox, German measles, measles, mumps or whooping 

 cough, this is not necessary if the person has had the disease 

 before, and is, therefore, immune. In diphtheria the incu- 

 bation period is short (from one to five days), but carrier 

 cases are so common that all those who have been exposed to 

 diphtheria should have their throats examined and a sample 

 taken from the throat for bacteriological examination. 



Everyone takes typhoid and scarlet fever seriously, but 

 T f measles and whooping cough are often re- 



iur i j garded as unimportant and negligible in- 



-^ . fections. This is by no means the case. 



r u Measles is an important cause of in- 



validism in the army. " In the Union Army 

 during the Civil War, there were 76,000 cases with more than 

 5,000 deaths. Among the Confederates whole brigades were 

 temporarily disbanded on this account in the early part of 

 the war." Among the civil population measles is in most 

 cities the cause of more deaths than either typhoid or scarlet 

 fever, while whooping cough stands very close to it. Above 

 all it should be remembered it is to young babies that these 

 maladies are most deadly. Measles and whooping cough 

 are more than five times as fatal in infants under one year 

 of age as in children over five. Every possible effort should 

 therefore be made to protect infants from contact with those 

 who have any symptoms of what may prove an infectious 

 disease. 



IMMUNITY AND ITS CONTROL 



Every attack of communicable disease is a struggle be- 

 v . 1 tween the invading microbes and the body, 



p . for as soon as foreign germs enter, the sol- 



dier cells of the blood attack the invaders 

 while the tissues of the body begin to produce chemical sub- 



38 



