INFLAMMATION AND PHAGOCYTOSIS 139 



the muscle fibres can be observed in the interior of the 

 phagocytes. The bacilli or cells taken up by the phagocytes 

 become distorted, and before disappearing lose their affinity 

 for stains. In the various cases of immunity the phagocytes 

 digest the bacteria by means of endo-enzymes. 



The surface of the skin, and in particular of the mucous 

 membrane, is being continually besieged by bacteria, and 

 never a moment passes but some point in the body is in a state 

 of subinflammation. The phagocytes are in continual opera- 

 tion on the surface of the tonsils, of the mucous membrane of 

 the intestine, and of the alveoli of the lungs. 



Phagocytosis plays a pre-eminent part in chronic infections, 

 especially in tubercle, and the tubercle itself is a phagocytic 

 formation. In contrast to Baumgarten's contention that the 

 tubercle is built up by epithelial cells, fixed cells from the 

 diseased tissue itself, lung, liver, or kidney, Metchnikoff 

 and his pupils have proved that it is really composed of 

 migratory mesodermic cells which have come from elsewhere 

 to the infected point. Borrel followed the formation of the 

 tubercle from the time of the first contact between the white 

 corpuscles and the bacilli, and found that injected bacilli were 

 engulfed by the polymorphs while still in the circulation. The 

 polymorphs perish and degenerate (in two or three days) and are 

 followed by the macrophages which fuse together into a sort of 

 little plasmodium with several nuclei, which is characteristic of 

 the tuberculous lesion, and is called by the anatomists the 

 giant cell. Later, the tubercle may soften, and there may be a 

 new afflux of polymorphs attracted chiefly by the bacteria of a 

 secondary infection. 



In the squirrel-rat spermophilus, a rodent rather resistant to 

 tubercle, the phagocyted bacilli lose their staining properties, 

 degenerate, swell up and finally appear as yellowish bodies, 

 such as are never observed either in cultures or outside the cells, 

 and can only be residues of phagocytic digestion. In 

 another rodent, the jerboa, there is found, especially in 

 tubercle of the spleen, instead of bacilli amorphous bodies 

 built up of concentric layers, which are encrusted with 



