2$ ESSENTIALS OF BACTERIOLOGY 



Infection results through some damage of the superficial 

 layers. The injury may be very slight an expanded hair- 

 follicle may suffice to permit entrance of suppurative organ- 

 isms. 



The Conjunctiva. The micrococcus of trachoma, the 

 Koch-Weeks bacillus, considered to be the specific cause of 

 acute catarrhal conjunctivitis, or "pink eye," and the Bacillus 

 xerosis, are special germs found on the conjunctiva; the other 

 varieties of air- and water-organisms, and those usually 

 present on the skin, are also found. Loffler's bacillus and 

 the pneumococcus have been found in some forms of con- 

 junctivitis. The Koch- Weeks bacillus is the most contagious. 



A special diplobacillus, known as the bacillus of Morax- 

 Axenfeld, produces a stubborn form of conjunctivitis. 



The gonococcus is found in ophthalmia of the new-born. 



The Mouth. The mouth is a favorite seat for the devel- 

 opment of bacteria. The alkaline saliva, the particles of 

 food left in the teeth, the decayed teeth themselves, all fur- 

 nish suitable soil for their growth. 



Quite a number of germs have been isolated and their 

 properties partly studied. Many have some connection with 

 the production of caries of the teeth, as Miller has well shown 

 in his careful studies. The Leptothrix buccalis, found in 

 nearly all mouths, is a long chain or filamentous bacillus which 

 stains blue with iodin. It was formerly considered the cause 

 of tartar on the teeth. 



The Spirillum sputigenum, Spirochaeta dentium, Micro- 

 coccus gingivae pyogenes, Bacillus dentalis viridans, Bacillus 

 pulpae pyogenes, micrococcus of sputum septicemia, and 

 Micrococcus salivarus septicus are a few of the organisms 

 cultivated by Miller and Biondi from the mouth and sup- 

 posed to be separate varieties. Besides these, the pneumo- 

 bacteria, diphtheria bacillus, and tubercle bacillus are often 

 met with, the first two in the mouths of healthy persons. 

 The expired air in quiet respiration is free from bacteria, but 

 in coughing, sneezing, etc., large numbers of organisms are 

 violently ejected and the atmosphere about tubercular 



