DIAGNOSIS 205 



tiguous parts should be thoroughly washed out with sterile salt solution and 

 covered with a sterile dressing. About 12 hours later the dressing is removed, 

 a sterile loop or cotton swab is passed over the affected membrane and then 

 drawn over the surface of slant tubes of agar and blood-serum media the tubes 

 are incubated at 37C. for 18 to 72 hours. Slides should also be prepared. 



CONJUNCTIVA 



In addition to acute catarrhal, contagious conjunctivitis or pink-eye, caused 

 by the Koch- Weeks bacillus and ophthalmia neonatorum caused by gonococcus, 

 infections of the conjunctiva may be caused by a variety of organisms. After 

 cleansing and covering with a sterile dressing for a number of hours, slides 

 should be made and stained with methylene blue and by Gram's method, cul- 

 tures should be made on appropriate media. The material for examination is 

 obtained by passing a sterile cotton swab over the affected part. 



SYPHILIS AND TUBERCULOSIS OF THE EYE 



Chancres, though rarely observed in such localities, do occur on the lids and 

 conjunctiva, suspicious ulcers should be examined for treponema pallidum and a 

 Wassermann test made. 



Secondary, tertiary and congenital syphilis frequently cause inflammation 

 of the cornea, sclera, iris, ciliary body, choroid, retina and optic nerve, occasion- 

 ally tuberculosis does the same. 



In suspected cases a Wassermann test should be made and if negative a 

 tuberculin test is made. 



DISEASES OF THE EAR 



The auricle and external auditory canal are subject to all the infections that 

 affect the skin, but they are much less frequently attacked. The technique 

 of bacteriological diagnosis of infections of those parts is the same as in similar 

 infections of the skin. 



The diphtheria bacillus sometimes infects the external auditory canal, this 

 is most apt to occur when the throat is also involved and technique for examina- 

 tion is the same as when examining the throat for diphtheria bacilli. 



OTITIS MEDIA 



Nearly all infections of the middle ear follow, or occur as extensions of, naso- 

 pharyngeal infections. When they progress to suppuration and discharge 

 through the external auditory canal secondary infection from the air frequently 

 results. 



Bacteriological diagnosis is usually called for when the disease has progressed 

 to suppuration and pus is discharging through the external meatus. In such 

 cases the ear is thoroughly cleansed by syringing with sterile salt solution, a 

 plug of sterile cotton is then placed in the external meatus, 6 to 24 hours later 

 the auricle is asepticized, the plug removed, and a sterile cotton swab is passed 

 into the external auditory canal to collect the exudate. Slides and cultures on 



