BACTERIUM TUBERCULOSIS 141 



Toxins. The peculiar evidences of tuberculosis are 

 due to the toxins elaborated by the causative germ, 

 which are both extracellular and endotoxic. The former 

 produce the constitutional symptoms of fever and 

 general depression of health. They are also probably 

 responsible for some of the inflammation in the neigh- 

 borhood of tubercles. The endotoxins, on the other 

 hand, produce the peculiar local inflammation called 

 the tubercle, and cause its degeneration into caseous 

 material. During an infection with tuberculosis there 

 will be developed in the body fluids a very slight 

 amount of substance as antibody to these endo- and 

 extracellular poisons. It is of little importance in 

 the diagnosis, treatment, or protection of the indi- 

 vidual, and a specific resistance to tuberculosis is not 

 acquired by passing through an attack, although it 

 is said that a tuberculous person cannot be reinfected 

 with tuberculosis. Recovery ensues when the health of 

 the individual and his tissues is strong enough to 

 inhibit the multiplication of bacilli. 



Predisposing Causes and Transmission. A lighting 

 up of the disease may occur when the resistance 

 weakens by reason of some acute disease, bad habits, 

 and the like. Tuberculosis spares no walk of life, but 

 is more common where the lack of body care reduces 

 resistance. It is preeminently the disease of crowded, 

 dark, illy ventilated, badly drained tenements. It comes 

 in the pulmonary form frequently, as an infection 

 on top of an acute cold. The disease is spread in by 

 far the largest percentage of cases by the direct inhala- 

 tion of germs coughed out by a tuberculous person 

 and contained in dust contaminated by tuberculous 



