DISTRIBUTION OF BACILLI. 



219 



retains its form and staining power for a much longer period 

 than most organisms. This is true of the bacilli both in 

 cultures and also in the tissues. 



As regards their position in the tissues, the bacilli are 

 usually scattered irregularly or in small groups amongst the 

 cells or granular material. Most of the bacilli lie free 



FIG. 59. Tubercle bacilli in section of human lung in acute phthisis. 

 The bacilli are seen lying singly, and also in large masses to left of field. 

 The pale background is formed by caseous material. 



Stained with carbol-fuchsin and Bismarck-brown. x 1000. 



between the cells in the connective tissues, and their 

 occurrence within the cells is proportionately not common, 

 there being in this respect a contrast to what is seen in the 

 lesions in leprosy. Occasionally we find them within the 

 giant cells, in which they may be arranged in a somewhat 

 radiate manner at the periphery, occasionally also in epithel- 



