312 PATHOGENIC BACTERIA. 



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 

 consist in nodes, nodules, or collections of agminated 

 nodules, called tubercles, scattered irregularly through 

 the tissues, which are devitalized or disorganized by 

 their presence. When tubercle bacilli are introduced 

 beneath the skin of a guinea-pig, the animal shows no 

 sign of disease for a week or two ; it then begins to lose 

 appetite and gradually to diminish in flesh and weight. 

 Examination at this time will show a nodule at the point 

 of injection and enlargement of the neighboring lymphatic 

 glands. The atrophy increases, the animal shows a febrile 

 reaction, and dies at the end of a period of time vary- 

 ing from four to twelve weeks. Post-mortem exam- 

 ination shows a cluster of tubercles at the point of 

 inoculation, enlargement of lymphatic glands both near 



