INFLAMMATION AND LEUCOCYTE RESPONSE 57 



Menkin, Opie, and others have shown that when one injects dyes, 

 proteins, etc., either locally or intravenously the material is picked 

 up and fixed by areas of inflammation. The final process in recov- 

 ery is the replacement of dead tissue by connective tissue which 

 through changes in the fibers and shrinkage forms scar tissue. It 

 is obvious that if scar tissue forms in the walls of the esophagus, 

 intestines, ureters or urethra, the lumen will be narrowed by a stric- 

 ture and functional impairment will result. The numerous investi- 

 gations relative to the cellular (phagocytic) defense of the body 

 against streptococcus, staphylococcus, and other infectious agents 

 which have been cited all point to the great importance of fixed and 

 free mononuclear cells rather than the neutrophiles in combating 

 the infection. 



Chronic Inflammation. — Formation of a Tubercle. — In tuber- 

 cular and many chronic inflammations it has been noted that there 

 may be very little hyperemia, local increase in temperature or 

 exudation of fluid. Neutrophiles may appear early, but they are 

 soon supplanted by mononuclear celLs. Pns may be formed as in 

 the ''cold abscesses" of tuberculosis with little systemic disturb- 

 ance. 



Maximow, as well as Sabin, Cunningham, and Doan, has given 

 excellent descriptions of the formation of the tubercle under experi- 

 mental conditions. When tubercle bacilli set up a primary infec- 

 tion in tissue, there is an early appearance of neutrophiles, mono- 

 nuclear cells, a few red cells, and some fluid. The first inflam- 

 matory reaction subsides and the exudative process disappears. 

 The mononuclear cells then increase in number and collect in a 

 mass around the tubercle bacilli. The mononuclear cells, according 

 to Maximow, gradually undergo transformation. Their cytoplasm 

 becomes more abundant and acquires the capacity to stain with 

 acid dyes. Near the center of the mass one or more "giant cells" 

 appear. These are the giant cells of Langhans. They are described 

 as "protoplasmic masses with the nuclei arranged in a peripheral 

 ring or in an equatorial band. " It is Maximow 's opinion that they 

 are formed by the fusion of the large mononuclear or epithelioid 

 cells and that mitosis of the nuclei follows. 



Sabin et al. classify the mononuclear cells forming the tubercle 

 as monocyte?. They did not observe fusion of monocytes to form 



