PLATE VIII. TUBERCULOUS CAVITIES IN THE LUNGS 



In the upper parts of this lung, the tuberculous 

 tissues have been destroyed, broken down and cast ofr, 

 leaving rough irregular cavities communicating with 

 the bronchial tubes. In the walls of these cavities tu- 

 bercle bacilli thrive and may be discharged in large 

 numbers with the sputum. 



