Tuberculosis. 



307 



^\ 



'^,. 



by the formation of a firm bacony connective tissue of the nature 



of a confluence of fibrous tubercles, or in other words a 



chronic tuberculous inflammation. Lymph glands, the seat of 



tuberculous infiltration, may grow to enormous 



masses as thick as an arm, or the size of loaves of 



bread. .Bunches of tuberculous pulmonary lobules 



are converted into dry necrotic masses as big 



as a fist and comparable in appearance to Edam 



cheese or Swiss cheese ; or sometimes whole 



lobes are changed into large, lumpy masses, 



hard, weighing over a kilogram, and riddled 



with points of cheesy softening. 



Tuberculous an'ities, developing in the 

 areas of cheesy infiltration, are cavities varying 

 from the size of a nut or fist to a span [a span is 

 nine inches] and a half in diameter. They con- 

 tain a greasy, caseous and slimy mass of detritus 

 and are limited by a wall of pale, indurated 

 fibrous tissue or by the tissue of the organ modi- 

 fied by the dift'erent color shades given by the 

 tuberculous inflammation., and giving rise to the 

 cavities by degenerative changes affecting it. 



These more important types of tuberculous 

 changes* may combine in various ways anil 

 there are apt to be, too, special modifications due 

 to peculiarities of the tissues in the various types 

 of animals. While cheesy areas in cattle usually 

 have an intense yellow color, in horses and car- 

 nivora they are apt to be whiter and sometimes 

 quite milky. They are not at all uniform in 

 consistence, sometimes dry and cheesy, some- 

 times soft and pultaceous or possibly broken 

 down into a pus-like fluid. Caseation may in 

 some instances be absent and the tubercles 

 may be of. a more cellular character, look- 

 ing like the tissue of lymph glands ; or they may become hard 

 and fibrous (in horse). 



The entrance of tubercle bacilli into a tissue generally occurring 

 at places where lymph nodes He exposed (pharynx, intestine) at first 

 causes a primary local tuberculosis at the point of infection. How- 



*Foi- detailed examples cf. KUt, LcIiiIiikIi d. iii>c.~. imtli. Aunt., 11. .\iitl., 

 Stuttgrart, 100.'?. F. Enke. 



'■-i 



Fig. 70. 



'riiherculoiis rib of 

 cow (fresli sec- 

 tion). 



