AVENUES OF EXIT OF INFECTIOUS AGENTS. 153 



Perhaps for completeness we should add that they 

 also make their exit in the lachrymal and vaginal secre- 

 tions ; but since there is no specific infection of the uterus, 

 and only a few of the conjunctiva, these exits are not of 

 sufficient importance to justify an individual place in 

 our division of the avenues of exit. Furthermore, the 

 inflammatory conditions found in both these situations 

 might, with perfect propriety, be included under divis- 

 ion three. 



The exit of a micro-organism from the body depends 

 upon the character and location of the disease, namely, 

 whether it be local or general. If a disease is localized 

 in such a portion of the body as communicates with the 

 exterior, the germs make their exit by that channel. 

 Thus, in inflammatory conditions of the lungs, the 

 offending microbes are discharged by way of the 

 passages that lead from them to the exterior. Similarly, 

 in infections of the uterus the infecting agents make 

 their exit by way of the vagina. But if, on the other 

 hand, the disease be general, that is, if the germs are 

 circulating in the blood, there may be various avenues 

 of exit, the urine, the skin, the sputum, the stools, and 

 sometimes, through the bites of insects. 



Until quite recently, many diseases that we now know 

 to be general were looked upon as localized infections, 

 and therefore their agents were supposed to leave the 

 body by a single channel; but later researches have so 

 modified our views that we now believe there are very 



