60 DUST AND ITS DANGERS. 



When the tubercle bacilli get into the bodies 

 of predisposed individuals and begin to grow 

 they stimulate the tissues about them so that 

 little new-formed masses of cells appear about 

 and among the growing germs. These cell 

 masses are called tubercles. Sometimes larger 

 masses of new cells are developed, which re- 

 place considerable portions of the tissues and 

 organs in which the bacilli have lodged. After 

 a time, especially in the lungs, the new-formed 

 tissue, containing sometimes enormous num- 

 bers of the living tubercle bacilli, gradually 

 disintegrates or breaks down, and this broken- 

 down germ-laden material may then be dis- 

 charged with the mucus from the bronchial 

 tubes day after day in considerable quantities 

 for months or even years, in the expectoration, 

 new bacilli forming as fast as the old are dis- 

 charged and sometimes even much faster. 



Tuberculosis may have its seat in other parts 

 of the body than the lungs, but with the lung 

 affection alone we are now concerned. 

 ' This then is the great primary fact which is 

 of extremest significance to us in our present 

 study ; namely, that every person suffering 



