224 PATHOGENIC BACTERIA. 



bacilli in the milk of cattle affected with tuberculosis. It 

 does not seem necessary that tuberculous ulcers shall be 

 present in the udders ; indeed, the bacilli have been 

 demonstrated in considerable numbers in milk from 

 udders without tubercular lesions discoverable to the 

 naked eye. 



The meat from tuberculous animals is less dangerous 

 than the milk, because the meat is nearly always cooked 

 before being eaten, while the milk is generally taken 

 uncooked. The bacilli enter the intestinal lymphatics, 

 sometimes produce lesions immediately beneath the mu- 

 cous membrane, and lead later on to the formation of 

 ulcers ; but generally they first involve the mesenteric 

 lymphatic glands. The thoracic duct is sometimes af- 

 fected, and from such a lesion it is easy to understand the 

 development of a general miliary tuberculosis. The oc- 

 casional absorption of tubercle bacilli by the lacteals, and 

 their entrance into the systemic circulation and subse- 

 quent deposition in the brain, bones, joints, etc., are sup- 

 posed to explain primary lesions of these tissues. 



Infection is said also to take place occasionally through 

 the sexual apparatus. In sexual intercourse tubercle 

 bacilli from tuberculous testicles may be discharged into 

 the female organs, with resulting tuberculous lesions. 

 The infection in this way generally is from the male to 

 the female, primary tuberculosis of the testicle being 

 much more common than primary tuberculosis of the 

 uterus or ovaries. 



While most probably rare, in comparison with the 

 preceding, wounds also are avenues of entrance for the 

 tubercle bacilli. Anatomical tubercles are not uncom- 

 mon upon the hands of anatomists and pathologists, 

 most of these growths being tuberculous in character. 

 An interesting fact concerning these dermal lesions 

 is the exceedingly small number of bacilli which they 

 contain. 



The macroscopic lesions of tuberculosis are too familiar 

 to require a description of any considerable length. They 



