TUBERCULOSIS. 315 



lescence, but only one observer, Baumgarten, has found 

 signs of this process in giant-cells. 



While these changes are in progress in the epithelioid 

 cells leucocytes may collect in such numbers as to 

 become the chief components of the tubercle. In the 

 further progress of coagulation-necrosis, the most deli- 

 cate cells (the leucocytes) die first ; and not infrequently 

 a tubercle rich in leucocytes shows extensive degenera- 

 tion of these cells, with recurring prominence of the 

 original epithelioid cells. 



It has been taught by some that the giant-cells are 

 produced by the union of the leucocytes, but after a care- 

 ful study of these cells I am convinced that such an 

 origin for these monstrous cells must be very rare, and 

 that they result solely from the epithelioid cells. 1 



Giant-cells are not always formed, for the- necrotic 

 changes are sometimes so violent and widespread as to 

 convert the whole cellular mass into a granular detritus 

 of unrecognizable fragments. 



Tubercles are constantly avascular, the avascularity 

 being an important factor in the necrosis of the larger 

 tuberculous masses, but probably playing no important 

 part in the degeneration of the small tubercles, which is 

 purely toxic. 



Tubercles may be developed in any tissue and in any 

 organ. In whatever situation they occur, space is occu- 

 pied at the expense of the tissue, whose component cells 

 are pushed aside or else included in the nodule. In mil- 

 iary tuberculosis of the kidney it is not unusual to find a 

 tubercle including a whole glomerule, and resolving its 

 component thrombosed capillaries and epithelium into 

 necrotic fragments. 



As almost all tissues contain a supporting tissue-frame- 

 work of connective-tissue fragments, some of these must 

 be embodied in the new growth. The fibres which pos- 

 sess little vitality are more resistant than cells, and, after 

 all the cells of a tubercle have been destroyed, will be 



1 International Medical Magazine, vol. i., No. io, 1892; vol. iii., No. 2, 1894. 



