46 INFECTION AND IMMUNITY. 



the case of traumatism, as in incarcerated hernia, 

 or in severe constipation, or when the normal 

 resistance of the intestines has been much dis- 

 turbed by improper food. 



Sometimes an attack of a disease represents a 

 recrudescence or reinfection by organisms which 

 have persisted at some point following a previous 

 attack. Relapses of typhoid fever and recurrences 

 of facial erysipelas, and frequently the flaring up 

 of an old (latent) gonorrhea, illustrate this. Acute 

 miliary tuberculosis, or tuberculous meningitis, 

 may follow the escape of bacilli into the circulation 

 from an unsuspected focus in a peribronchial 

 lymph gland. This manifestly is not autoinfec- 

 tion or endogenous infection, since, even in the 

 old latent foci, the infection dates back to a prior 

 invasion. 



