INFECTIOUS DISEASES 421 



cold unless we take disease germs into the body. The 

 germs come from persons who have a cold, and are found 

 in whatever is given off from the nose or throat. Tiny 

 drops of saliva and mucus are driven out with every 

 cough and sneeze, and when they are dried, their germs 

 float in the air as dust. Millions of the germs are scat- 

 tered through the air from every spot of dried phlegm 

 which has been spit upon the floor or pavement, and mil- 

 lions more may be spread from every handkerchief on which 

 the nose has been blown. Colds are extremely common, 

 and thus the germs are widely spread and are likely to be 

 found wherever the air is close and foul. Great numbers 

 float in the air of crowded meeting places, but those who 

 attend the meetings often suppose that they take cold 

 from drafts of fresh air, when the real cause is the germs 

 floating in the foul air. Fresh air is the best of all . pre- 

 ventives of colds. 



729. Danger from colds. A cold is usually a harmless kind of 

 sickness, but it is not always so. Some mild colds are caused by the 

 germs of the grippe, or of pneumonia, or of erysipelas, or of whooping 

 cough, and are the means of spreading the diseases to others in bad forms. 

 Many mild sore throats are caused by the germs of diphtheria which 

 may produce the disease in a deadly form in the next person who takes 

 the germs. Thus we should consider any cold to be serious, and should 

 do all that we can to prevent the germs from spreading. 



730. Prevention and cure of colds. Colds are spread 

 chiefly by means of dried sputum, just as tuberculosis is 

 spread, and may be prevented or cured in the same way 

 as tuberculosis (p. 392). A person who has a cold should 

 keep away from other people. He should sleep in a clean 

 room alone, and with a window open to admit fresh air 

 day and night. None of the phlegm should be spit upon 

 the floor or pavement, but it should be caught upon hand- 

 kerchiefs, and several clean ones should be used each day. 



