430 HEALTH AND DISEASE 



Ex-President Roosevelt said in one of his latest messages to 

 Congress : — 



" There are about 3,000,000 people seriously iU in the United States, of 

 whom 500,000 are consumptives. More than half of this illness is prevent- 

 able. If we count the value of each life lost at only $1700 and reckon the 

 average earning lost by illness at $700 a year for grown men, we find that 

 the economic gain from mitigation of preventable disease in the United 

 States would exceed $1,500,000,000 a year. This gain can be had through 

 medical investigation and practice, school and factory hygiene, restriction 

 of labor by women and children, the education of the people in both pub- 

 lic and private hygiene, and through improving the efficiency of our health 

 service, municipal, state, and national." 



Infectious Diseases and Quarantine. — One of the important 

 means for prevention of the spread of diseases caused by bacteria 

 or Protozoa is by quarantine. The board of health at once isolates 

 any case of disease which may be communicated from one person to 

 another. This is called quarantine. No one save the doctor or 

 nurse should enter the room of the person quarantined. After the 

 disease has run its course, the clothing, bedding, etc., in the sick 

 room is fumigated. This is usually done by the board of health. 

 Formaldehyde in the form of candles for burning or in a liquid 

 form is a good disinfectant. The room should be tightly closed 

 to prevent the escape of the gas used, as the object of the disin- 

 fection is to kill all the disease germs left in the room. 



Immunity. — In the prevention of germ diseases we must fight the 

 germ by attacking the parasites directly \vith poisons that will kill 

 them (such poisons are called germicides or disinfectants), and 

 we must strive to make the persons coming in contact with the 

 disease unlikely to take it. This insusceptibility or immunity 

 may be either natural or acquired. Natural immunity seems to be 

 in the constitution of a person, and may be inherited. Immunity 

 may be acquired by means of such treatment as the antitoxin 

 treatment for diphtheria. This treatment, as the name denotes, 

 is a method of neutralizing the poison (toxin) caused by the bacteria 

 in the system. It was discovered a few years ago by a German, 

 Von Behring, that the serum of the blood of an animal immune 

 to diphtheria is capable of neutralizing the poison produced by 

 the diphtheria-causing bacteria. Horses are rendered immune 



