FIBROSIS AND HYPERPLASTIC TUBERCULOSIS 335 



tubercles or fibrous nodules may still contain live virulent tubercle 

 bacilli. These finally disappear entirely or they remain latent for a 

 long time, and later lead to a fresh outbreak of the tubercular process. 

 Fibrosis, caseation, and calcification may also continue more or less 

 simultaneously in numerous tubercles in a larger area and lead to 

 the formation of large masses of fibrous connective tissue, caseous 

 or calcereous material. 



Cryptogenetic Tubercular Infection. The tubercle bacillus, as 

 already pointed out, generally enters the body of man and the sus- 

 ceptible lower animals through the respiratory passages or through the 

 gastro-intestinal tract. It is in these parts and their lymph glands that 

 the tubercular lesions generally first make their appearance. The 

 bacillus, however, may enter the system through its usual portals of 

 entrance and may not produce morbid changes in those places, but be 

 carried away by the lymph or blood current to produce its first lesions 

 at places which have no direct open communication with the outside 

 world. Such places are, for instance, the bones, the periosteum, and 

 the synovial membranes of the joints, the brain, the testicles, etc. 

 This is known as a cryptogenetic infection, which means an infection 

 of secret or hidden origin. Tubercular infections, however, which do 

 not first involve the regional lymph glands near their portal of entrance 

 are, on the whole, very rare. 



Fungous Tubercular Granulations. The tubercle bacillus may 

 become localized from the beginning, not merely at a single point, but 

 over a larger area of a certain structure. It may also rapidly spread 

 locally and lead to the formation of numerous tubercles between 

 which, in consequence of the inflammatory irritation, a great deal 

 of ordinary inflammatory granulation tissue develops in which the 

 tubercles lie embedded. These soft spongy masses which develop are 

 called fungous tubercular granulations. They are seen particularly 

 in the synovial membranes of the joints and the bursse. 



Solitary Tubercles. Sometimes masses of tubercular granulation 

 tissue form a single round or oval mass of the size of a hazel nut or 

 walnut. Tubercles of this kind are called solitary tubercles. They are 

 not infrequently seen in the brain or its membranes of man and cattle. 

 These round masses, of course, do not represent one tubercle, but 

 are made up of numerous miliary and submiliary tubercles. 



Fibrosis and Hyperplastic Tuberculosis. As has already been stated 

 the tubercle may in healing undergo a fibrosis and become changed 

 into a fibrous nodule. When this process continues in a larger number 

 of tubercles over a larger area it leads to the formation of a consider- 

 able amount of fibrous connective tissue. It also occurs, particularly 

 in the intestines of man, that a tubercular process is comparatively 

 mild from the beginning and does not give rise to many cellular 

 tubercles, with subsequent caseation, but rather leads to the forma- 

 tion of a very large amount of fibrous connective tissue. This form 

 of tuberculosis is known as a hyperplastic tuberculosis. 



