144 BACTERIA OF DISEASE 



nary constitution, if suitably nourished, can be cured by living 

 in the open air. This pest could probably be wiped out within 

 ten years, if the habit of spitting could be stopped. The spores 

 and plants are readily carried away in the air from the dried 

 sputum to be inhaled again and so spread the disease. The 

 bacteria causing lockjaw, or tetanus, are especially abundant in 

 the soil in certain localities. Through wounds they are carried 

 into the system. These and some other bacteria are peculiar in 

 that they can not grow in the presence of oxygen. Conse- 

 quently the dangers of infection are great in deep wounds. An 

 immediate cauterization of the entire surface of the wound will 

 kill the organisms. Other well known bacterial diseases are 

 pneumonia, diphtheria, Asiatic cholera, typhoid, and splenic fevers 

 and grippe. It should be noted that many diseases as smallpox, 

 malaria, hydrophobia, yellow fever and probably scarlet fever, 

 etc., are due to a low order of microscopic animal life. These 

 bacteria are either localized, as in the lungs, throat, intestines, 

 or are generally distributed throughout the system. The symp- 

 toms of the disease are largely due to the products of decompo- 

 sition caused by the growth of the bacteria or by secretions from 

 the bacteria themselves all of which act as poisons and are com- 

 monly referred to as toxins. In other cases the toxins are formed 

 by the infected plants or animals owing to the disturbance of its 

 growth and nutrition by the bacteria in its tissues. 



These bacteria are constantly rinding their way into our bodies 

 by means of the breath but so long as the system is in a healthy 

 condition there is only slight danger of the organism gaining 

 a foothold. Just how the system is able to combat the growth of 

 these plants is now the subject of earnest investigation. Certain 

 diseases, as mumps, measles, whooping-cough, smallpox, etc., 

 usually occur but once and it is probable that substances are 

 formed in the body as a result of the presence of the bacteria or 

 animal organisms that prevent a second growth of the germs and 

 the individual thus becomes immune to further attacks. The 

 formation of such a substance is known to occur in the case of 

 diphtheria. The bacteria of this disease occur in the upper air 

 passages of the throat and secrete a poison or toxine that affects 



