CHAPTER XYIII. 



Tubercalosis— Microscopic appearance of miliary tabercles— Encapsalation 

 of tuberculous foci — DiflFuse caseation — Cavity-formation — Primary infection 

 —Modes of infection— Location of the bacilli in the tissues — Staining-pecu- 

 liarities— Organisms with which baciUug tubcreuUms may be confounded- 

 Points of differentiation. 



Should the animal succumb to neither of the septic 

 processes just described, then its death from tuberculosis 

 may be reasonably expected. 



When this disease is in progress alterations in the 

 lymphatic glands nearest the seat of inoculation may 

 be detected by the touch in from two to four weeks. 

 They will then be found to be enlarged. Though not 

 constant, tumefaction and subsequent ulceration at the 

 point of inoculation may sometimes be observed. Pro- 

 gressive emaciation, loss of appetite, and difficulty in 

 respiration point to the existence of the general tuber- 

 cular process. Death ensues in from four to eight 

 weeks after inoculation. At autopsy either general or 

 local tuberculosis may be found. The expressions of the 

 tubercular process are so manifold and in different ani- 

 mals vary so widely the one from the other, that no 

 rigid law as to what will appear at autopsy can a priori 

 be laid down. 



The guinea-pig, which is best suited for this experi- 

 ment because of the greater regularity of its suscepti- 

 bility to the disease over that of other animals usually 

 found in the laboratory, presents, in the main, changes 

 that are characterized by a condition of coagulation- 



