TUBERCULOSIS. 265 



excited a migration of leukocytes, and surrounding the epi- 



FIG. 105. 



FIG. 104. 



Tubercle bacilli in giant-cell (from tuber- Tubercle bacilli (from a colony on 

 culosis of horse). X 600 (Cheyne). blood-serum), showing the wavy 



parallel lines. X 500 (after Koch). 



FIG. 106. 



A tubercle from a case of tuberculosis of the liver. A multinucleated giant-cell 

 occupies the centre. Around is an area of commencing caseation and outside 

 this a zone consisting principally of fibroblasts, and, to a less extent, of leuko- 

 cytes. The leukocytes are most numerous on the side where caseation is 

 most advanced. X 250. 



thelioid cells we find a layer of smaller lymphoid cells, both 

 often being supported by a fine connective-tissue reticu- 



