STRUCTURAL CHANGES DUE TO DAMAGE. 



333 



Phagocytes do incorporate bacteria ; but if those bacteria are viru- 

 lent, the phagocyte either refuses to take them within its cytoplasm, 

 or, after doing so, suffers degeneration or necrosis. It has no pecu- 

 liar immunity against the action of the bacteria. On the other 

 hand, it has been shown that the fluids of the body are capable of 

 diminishing the virulence of bacteria or of killing them. It often 

 takes some time for the production of the substances that have this 

 effect, and their elaboration is frequently too tardy to check the 

 destructive action of the bacteria. But upon the surface of granu- 

 lations, from which absorption is slow or does not take place, the 

 effects of the tissue-fluids have been studied and an attenuation of 

 bacteria (decrease in their virulence) observed. These attenuated 



FIG. 295. 



Phagocytes from granulations infected with virulent anthrax bacilli. (Afanassieff.) a, thread 

 of bacilli, partly within and partly outside of a phagocyte. Both portions show a vacu- 

 olation of the bacilli, indicative of their degeneration, d, thread almost entirely incor- 

 porated. Within the cell the incorporated bacilli lie in vacuoles in the cytoplasm ; prob- 

 ably digestive vacuoles. In 6 and e similar appearances are presented, c, degenerating 

 thread of bacilli from the fluid of the granulations. Vacuolation has also taken place in 

 this thread, showing that the fluids of the granulations have a destructive influence upon 

 the bacilli. 



bacteria may be taken up by phagocytes with impunity and subse- 

 quently digested within their cytoplasm (Fig. 295). 



The digestion and removal of degenerated or dead materials 

 appear, then, to be the useful rdle played by phagocytes. They 

 appear to be the active agents in the absorption of organic frag- 

 ments, such as fibrin, macerated necrotic tissue, etc., which may be 

 present in the tissues of the body (Fig. 296). 



The majority of phagocytes are probably leucocytes, identical with 



