292 BACTERIOLOGY. 



necrotic process. Around the periphery of this area 

 may sometimes be noticed large multinucleated cells, 

 the nuclei of which are arranged about the periphery 

 of the cell or grouped irregularly at its poles. The 

 arrangement of these nuclei as observed in sections 

 is usually oval, or somewhat crescentic. In the tuber- 

 cles from the human subject these large " giant-cells," 

 as they are called, are quite common. They are much 

 less frequent in tubercular tissues from lower ani- 

 mals. 



Round about the 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 homoge- 

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

 be imbedded in a delicate network of fibrinous-looking 

 tissue. 



This fibrin-like network in which these bodies lie, and 

 which is a common accompaniment of giant-cell forma- 

 tion, 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 speak- 

 ing is the zone of so-called " grauulation tissue," and 

 consists of leucocytes, granulation cells, fibrin, and the 

 fibrous remains of the organ; the irregularly oval, gran- 

 ular bodies which take up the stain 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 surrounding tissues or 

 fuses with a similar zone surrounding another tubercu- 

 lar focus. This may be taken as a description of the 

 typical miliary tubercle. 



Diffuse CASEATioisr. — The diffuse caseation, as said, 

 plays a more important role in the tuberculous lesion, 



