INFECTIVITY OF EXCRETIONS. 37 



of primary tuberculosis of the mesenteric lymph 

 glands indicates that it probably occurs. 



Rectum. Gonorrhea, septic infection of hemor- Rectum and 



, . , , . Genito- 



rhoidal Veins. Urinary 



Urethra. Gonorrhea, syphilis; "simple" ure- 

 thritis due to other causes. 



Bladder and Ureters. Infection usually second- 

 ary, by extension or from the blood stream. 



External Genitals. Hard and soft chancres. 

 Diphtheria in girls. 



Female Genital Tract. Gonorrhea, especially in 

 the cervix, which is covered by soft cuboidal epithe- 

 lium. The vagina is quite resistant owing to its 

 covering of pavement epithelium and the bacteri- 

 cidal character of its secretion. Virulent pyogenic 

 organisms sometimes are found in the normal 

 vagina and they may occasionally be responsible 

 for puerperal infections. 



The above refers to primary invasion. It is well 

 known that many of these surfaces and the organs 

 which they cover are frequently involved subse- 

 quent to initial infection at some other point. This 

 is secondary, or, better, metastatic infection. 



Excretion of Micro-organisms. 

 In the transmission of an infection from person 

 to person, without the intervention of an inter- 

 mediate host (insects), the process naturally pre- 

 supposes that the micro-organisms are excreted or 

 discharged from the body of the patient through 

 one channel or another. Eegarding the likelihood 

 of transmission, in the event of excretion, this 

 will depend on the character of the organism, its 

 viability under the conditions of excretion, the in- 

 fection atrium which it demands, and whether or 



