46 DUST AND ITS DANGERS. 



several other important organs of the body, are 

 provided with a series of very efficient filters, 

 through which the lymph has to pass in its 

 transit toward the blood current with which 

 it is to mingle. Now several of these living 

 filters, which we call " lymph-glands," little 

 reddish-white bodies, are grouped deep in the 

 chest at the root of the lungs, and are so 

 very effective that, although the lungs may 

 be crowded with inhaled dust particles stored 

 away permanently in out-of-the-way places, and 

 the lymph filters may finally become themselves 

 as black as your hat from its accumulation 

 (see Fig. 5) the dust rarely gets through them 

 and into the blood or other parts of the body. 



Thus far, in considering the safe-guards of 

 the body against inhaled dust, we have been 

 thinking only of those lifeless particles of one 

 kind or another which make up the inorganic 

 part of dust. How is it with bacteria, with 

 those dust particles which are quite inert when 

 dry in the dust, but which, when the moisture 

 and warmth and food they need are furnished, 

 may grow and multiply with great rapidity. 



