INFECTION ATRIA. 585 



bitz). The possibility of transmission of tubercu- 

 losis by means of tubercle bacilli in the spermatic 

 fluid should also be considered. Although no 

 proof of such infection exists, the presence of 

 bacilli in the spermatic fluid has been demonstra- 

 ted, particularly in men with tuberculous epididy- 

 mitis. 



Pulmonary tuberculosis is by far the most com- 

 mon form of the disease in man, and without doubt 

 this usually is due to inhalation of the dried and 

 pulverized sputum of tuberculous patients. Drop 

 infection may well occur in the case of those who 

 are in intimate contact with the sick. In kissing, 

 direct infection from mouth to mouth is a danger- 

 ous possibility. 



The reason for the inception of pulmonary tu- 

 berculosis in the apex in so many cases is not clear- 

 ly recognized, although it is often referred to the 

 relative immobility of this tissue, which renders 

 excretion more difficult and affords improper 

 aeration. These conditions not only allow the or- 

 ganisms to accumulate and to proliferate, but the 

 insufficient oxygen ation probably causes a low tis- 

 sue resistance. The suggestion which has been 

 made that apical tuberculosis is the result of ex- 

 tension of the disease from the cervical glands does 

 not correspond with the condition seen in tubercu- 

 losis of adults in whom the cervical adenitis is 

 commonly wanting. 



The "anatomic tubercle" is a primary infection 

 of the skin ; lupus vulgaris, it is supposed, may be 

 either a primary infection or secondary to tubercu- 

 losis in some other organ; ulcerative tuberculosis 

 is usually a secondary lesion, often occurring by 

 direct extension from tuberculous lymph glands. 



