Anatomical Changes. 543 



fected, but they may also be diseased when tubercles cannot be 

 demonstrated in the tissue of the udder, at least with the naked 

 eye. 



Of the central nervous system the brain is most frequently 

 affected. There may be several large tumors (tyroma, tuber- 

 culum solitarium) or a number of smaller cheesy foci. These 

 always involve the meninges and produce a tuberculous inflam- 

 mation. In such cases recent tubercles can be found at the 

 base of the brain, in particular in the region of the Sylvian 

 fissure (meningitis basilaris tuberculosa). As a rule this is 

 accompanied by acute internal hydrocephalus (very common in 

 calves after protective inoculation — Hutyra, Weber, Titze and 

 others). Similar affection of the spinal cord and its envelopes 

 is far more rarely met with, and when present it is usually 

 observed near tuberculous vertebrae. 



Tuberculous lesions are observed also as follows: In the 

 spongy substance of flat bones especially the ribs and vertebrae 

 but in exceptional cases also in the bones of the cranium and 

 of the pelvis; in long bones the marrow may be affected; in 

 articular cartilages of the long bones ; in the joints (exudative 

 inflammation with induration of the capsular ligaments result- 

 ing in villous proliferation and destruction of the cartilages, 

 according to Hamoir most common in the knee) ; on the nasal 

 mucous membrane with occasional involvement of the cartilages, 

 muscles and septum ; in the muscles of the body (usually cheesy 

 foci originating in the intermuscular lymph glands and occa- 

 sionally foci approaching the size of a bean scattered between 

 the bundles of muscle fibres) ; in the subcutaneous connective 

 tissue (firm tumors arranged in rosary-like order and cheesy 

 abscesses) ; very rarely in the skin, tendon sheaths of the ex- 

 tremities, penis, prostate gland and in the eye (tubercles in 

 the iris followed by caseous panophthalmia, or fibrinous iritis 

 without tubercles [Manleitner] ) . 



On post-mortem examination, especially in meat inspection, we dis- 

 tinguish between primary and secondary tuberculosis of the various 

 organs. The term primary is applied to lesions resulting from direct 

 infection from outside and spreading into the surrounding tissue from 

 the point of infection, either by direct growth or through the lymph 

 spaces and lymph vessels, but not by means of the blood stream. Second- 

 ary lesions are those resulting hEematogenically from infected embolisms 

 of the blood vessels, and are consequently found in the interstitial con- 

 nective tissue. They do not communicate with the outer world and 

 therefore rarely suppurate (Ostertag). According to the discussion on 

 page 530 the possibility of the occurrence of primary lesions of lympho- 

 genic or even hfematogenic origin in internal organs is not excluded. 



The term local tuberculosis is applied to lesions that have spread 

 or have become disseminated by direct growth only or through the lym- 

 phatics or one of the lesser circulations (pulmonary or portal) . If the 

 greater circulation was the means of disseminating the virus the result- 

 ing affection is referred to as generalized tuberculosis (Weigert, Oster- 

 tag). In the latter instance, if the infection was slight the resulting 



