DUST AND ITS DANGERS. 67 



from other diseases not infrequently the com- 

 mencements of tuberculosis." Now this is in 

 fact just what we do find. It is very common, 

 indeed, to find in those little filters at the root 

 of the lung, the lymph-glands which we have 

 spoken of in another chapter, both in adults 

 and in children small areas of tubercular dis- 

 ease, and nothing else in the whole body indi- 

 cating the presence of the germ. The disease 

 here has not been extensive enough to cause 

 any ill effects or give any symptoms. It may 

 be in an early stage or it may have existed for 

 a long time, or it may have altogether healed, 

 leaving only its unmistakable traces behind 

 (see Fig. 6). 



But more than this, even, we have learned 

 about the early stages of this disease. Many 

 observers, in cases of accidental death in ap- 

 parently healthy persons, have examined these 

 lymph filters (lymph-glands), and found them 

 in appearance perfectly healthy, and yet on 

 applying one of the most delicate and effective 

 tests, have found that after all they did, in a 

 considerable proportion of the cases exam- 

 ined, contain living tubercle bacilli. These 



