Natural iMMuNitY. 



disease germs. The unbroken skin does not 



absorb bacterial toxins. 



Subcutaneous connective tissue sometimes c u ^ 



Subcutaneous 



norms a formidable barrier to the entrance of Connective 

 pathogenic or disease germs even after they 

 penetrate the skin, although there are excep- 

 tions to this rule, also, as there are exceptions 

 to all general rules. 



The mucous membranes by reason of their jjucoug 

 moist condition favor the growth and develop- Membranes, 

 ment of a number of bacteria ; yet, by a certain 

 mechanical process, these are constantly ex- 

 creted and removed without causing the per- 

 fectly healthy any harmful result. 



Certain conditions of the conjunctiva favor xjje 

 the entrance of harmful germs, yet the con- Conjunctiva, 

 stant mechanical action of the eyebrows, the 

 eyelids, the eyelashes, the tear irrigation of the 

 surface of the conjunctiva and the germicidal 

 power of the tear salts ; the rapidity with which 

 the conjunctival epithelium is found to bring 

 about the process of repair, all of these agents 

 tend to protect this surface from infection, 

 healthful conditions being equal. 



While it is true that the cavity of the nose T^e 

 is a common ground for the camping of such Nose, 

 germs as the staphylococci, the streptococci, 

 the bacillus of diphtheria, etc., they are for the 

 most part held in abeyance owing to the filter- 

 ing action of the small hairs on the inner sur- 

 53 



