CASSATION 333 



however, not attained the larger size and the other characteristics 

 of the epithelioid cells. These are called lymphoid cells. While 

 all these newly formed cells appear and accumulate, they push aside 

 to a great extent the fibrous matrix of the connective tissue in which 

 they have developed. In consequence of this the young cellular 

 tubercle shows a rather scanty fibrous reticulum. If, however, the 

 cell proliferation has remained within moderate limits, when few 

 tubercle bacilli have been present and when they are, perhaps, of a 

 low type of virulency, or when the process has come to a standstill, or 

 when, in consequence of natural or artificial protective influences, a 

 process of healing is setting in, and when some of the newly formed 

 inflammatory cells have disappeared in consequence of softening, 

 liquefaction and absorption, the fibrous reticulum may become quite 

 abundant, particularly at the periphery. During the formation of 

 the tubercular inflammatory granulation tissue, in other words, the 

 tubercle, there is a complete lack of the formation of bloodvessels in 

 the newly formed tissue. In this respect the tubercle differs greatly 

 from ordinary inflammatory granulation tissue in which vascular buds 

 and new vessels are formed. The more virulent the infecting bacilli 

 the more rapid their multiplication, the sooner the retrograde degen- 

 erative processes become manifest and the more extensive they are 

 likely to be. The early degeneration of the tubercle is probably not 

 only due directly to the metabolic products of the tubercle bacillus, 

 but likewise to the fact that new vessels are not formed and that 

 preexisting ones are obliterated in the mass of the newly formed cells 

 of the tubercle. For this reason the tubercle from the beginning 

 suffers from a lack of proper nutrition. 



From the preceeding description it follows that a typical young 

 tubercle, presented to the unaided eye as a small, grayish-white, 

 perfectly translucent nodule generally contains three kinds of cells, 

 namely, multinuclear giant cells, epithelioid cells, and lymphoid cells, 

 all of which are derived and descended from fixed connective-tissue 

 cells. Such young tubercles occasionally also show some polynuclear 

 leukocytes which have wandered from the bloodvessels into the newly 

 formed inflammatory granulation tissue. Sometimes when the 

 tubercular infection is very mild, moderate, and slow in its action 

 upon the infected connective tissue there occurs simply an accu- 

 mulation of and an infiltration with small lymphoid cells between 

 which an epithelioid cell may be seen here and there, particularly 

 in thin sections. Such tubercles, composed almost exclusively of 

 lymphoid cells, with only a very few epithelioid cells, but without any 

 giant cells whatsoever, are called lymphoid tubercles. Unless there is 

 other evidence at hand they cannot be distinguished from an ordinary 

 subacute inflammatory small round-cell infiltration or focus. 



Caseation. The degeneration of the tubercle is known as its casea- 

 tion, because there is formed a rather dry, but soft, friable material 

 of the consistency and appearance and other physical properties 



