252 BACTERIOLOGY. 



are arranged about the periphery of the cell or grouped 

 irregularly at its poles. The arrangement of these 

 nuclei appears in the sections sometimes as ovals, again 

 they are somewhat crescentic in their grouping. In the 

 tubercles from the human subject these large "giant- 

 cells," as they are called, are quite common. They are 

 much less frequent in the tubercular tissues from the 

 lower animals. 



Round about this central focus of necrosis is seen a 

 more or less broad zone of closely packed small round 

 and oval bodies which stain readily but not homogene- 

 ously. They vary in size and shape, and are seen to 

 be imbedded in a delicate network of fibrinous-looking 

 tissue. 



This iibrin-like network in which these bodies lie, 

 and which is a common accompaniment of giant-cell 

 formation, is in part composed of fibrin, but is in the 

 main, most probably, the remains of the interstitial 

 fibrous tissue of the part. This zone of which we are 

 speaking is the zone of so-called " granulation tissue," 

 and consists of leucocytes, granulation cells, fibrin and 

 the fibrous remains of the organ ; the irregularly oval, 

 granular bodies which take up the staining are the 

 nuclei of these cells. The zone of granulation tissue 

 surrounds the whole of the tubercular process, and at 

 its periphery fades gradually into the healthy surround- 

 ing tissue or fuses with a similar zone surrounding 

 another tubercular focus. This may be taken as a 

 description of the typical miliary tubercle. 



Diffuse Caseation. — The diffuse caseation, as said, 

 plays a more important role in the tuberculous lesion, 

 both in the human and experimental forms, than does 

 the formation of miliary tubercles. In this a large 



