PREVENTION OF COLDS 475 



to infection from another person who has or is just recovering 

 from a cold. Sometimes the infection already exists in the indi- 

 vidual in a chronic but extremely mild state, and it may become 

 acute when the vitality or resistance is lowered. Eskimos and 

 Arctic explorers, in spite of the severe weather conditions, do not 

 have colds. When such explorers return to civilization they may 

 be infected by droplets sprayed by the coughing and sneezing of 

 people whom they meet, and they soon experience a severe cold. 



Prevention of colds. Since a cold is a droplet infection, it 

 generally travels through the sputum. Crowds in ill ventilated 

 places should be avoided. The germs can live only for a very short 

 time in air. Their culture medium is the air passages of human 

 beings. In crowds, it is impossible to avoid the sneezing or 

 coughing of other people. That is the way colds are spread and it 

 is the reason for the frequency of colds. Spitting spreads sputum- 

 laden bacteria into the air. If a person talks directly into the face 

 of another person, droplets of sputum are given off and inhaled. 



An experiment was made in England to show that droplets 

 from the mouth are spread. A certain member of Parliament was 

 asked to wash out his mouth with a culture of harmless bacteria 

 which, when plated, produce red colonies. He then made a loud 

 and eloquent speech. Petri dishes had been distributed in all 

 parts of the House of Parliament, even to the rear of the gallery. 

 When gathered, incubated, and the plates examined, all the ex- 

 posed dishes contained red colonies. The closed controls showed 

 none. The speaker had showered the entire house with micro- 

 scopic droplets containing the harmless bacteria. 



Coughs and sneezes must be covered in order to prevent the 

 spread of infections. When a person has a cold, he should use 

 gauze instead of handkerchiefs and the used gauze should be burned. 

 Some people seem to be more susceptible to colds than others. 

 This may be due to abnormalities in the nose or throat. Ade- 

 noids and infected or enlarged tonsils are excellent locations for 



