OTHER GERM DISEASES 447 



the blood stimulates the body to produce the germicide 

 for the smallpox germ. 



The germicide seems to remain in the blood for some time, perhaps 

 for years in some persons, and protects the body if other smallpox 

 germs enter. In some persons, however, the germicide disappears in 

 less than a year. We should be vaccinated every few years, or more 

 frequently if there is smallpox near us, in order that the germicide 

 may always be present in the body. If we are vaccinated by a good 

 doctor, with fresh vaccine virus, there is no danger. The doctor 

 should use only virus that has been purified, so that it cannot contain 

 other infecting germs. We should be vaccinated, not only for our own 

 sakes, but for the sake of others. The germs of smallpox live for 

 months in a dry condition; they may be preserved in books, clothing, 

 letters, etc. Hence we can never tell when we may catch the disease, 

 and give it to our friends and neighbors. We are not wiser than the 

 experience of the last 100 years. This experience teaches us that 

 while sanitary living helps to keep the germs down, it cannot help us 

 if they get into the blood, and if the blood has not prepared the proper 

 germicide for our defense. 



Vaccination against typhoid fever is now being carried out with 

 success, especially to protect armies in the hard, insanitary conditions 

 under which they are often forced to live. The germs of typhoid are 

 cultivated until they have multiplied, and produced their toxins. 

 Then the germs are killed, and small amounts of the dead germs and 

 the toxins are injected under the skin of the person to be protected. 

 Vaccination against typhoid ought to be an additional precaution, not 

 a substitute for sanitary measures. 



436. Other Germ Diseases. Scarlet fever and measles 

 are eruptive diseases, just as smallpox is. Both are 

 highly infectious, and both come chiefly in childhood. 

 The scarlet-fever patient often suffers little from the first 

 stages of the disease, but has very serious after-effects. 

 These may produce lifelong injury, even if they do not 



