CHAPTER IX. 
BACTERIOLOGICAL DIAGNOSIS. 
EXERCISE CVI. EXAMINATION OF BUCCAL SECRETION. 
DEFINITION. The secretion of the mouth, or saliva, is a mixed product derived in 
part from the mucous glands within the mouth and also from the parotid, submax- 
illary, and sublingual glands. In disease the normal character of the different parts may 
vary or there may be various exudates and growths present. 
COLLECTION. Material for bacteriological examination is best obtained by means of 
a sterile probang or forceps. This material may be examined directly by means of 
cover-glass preparations or by means of cultures. 
1. Method of Preparing Outfit. Wind a small piece of absorbent cotton on the end 
of a wire (about 1 mm. in diameter and 14 em. long). Thrust the other end of the 
wire through the cotton plug of a test-tube or fasten in a cork and sterilize at 150° C. for 
lhour. This with a tube of nutrient medium (usually Leoffler’s Blood serum) is placed 
in a box for transportation. 
2. Method of Using Outfit. The patient is placed in a good light and the probang 
gently but firmly rubbed over the suspected area of the throat and then drawn gently 
over the surface of the medium, both tubes securely stoppered and the outfit sent to the 
laboratory. The organisms to be sought for are B. diphtheriae, the pyogenic cocci and 
Monilia candida. 
BacCTERIUM DIPHTHERIAE.. 
The presence of this germ in the mouth usually results in a formation of a pseudo- 
membrane a portion of which is to be removed with a pair of forceps or by means of the 
outfit described above. It should, 1) be examined directly for the ae bacillus by 
smearing on a cover-glass and staining by following methods: 
a. Loeffier’s methylen blue. 
b. Gram’s stain. 
ce. Neisser’s stain: a. 1 gram methylen blue dissolved in 20 ce. of alcohol (96%), is 
added to 950 cc. of distilled water and 50 ec. of glacial acetic acid; b. 2 grams of bismark 
brown dissolved in a liter of distilled water. Films are stained in a. 2 to 3 seconds, washed 
in water, stained in 0. 3 to 5 seconds, dried and mounted. 
2) Usually, however, mere microscopical examination is not sufficient, and culture 
methods must be employed. In fact this method ought always to be used. 
In this case make smears on Loeffler’s blood serum and incubate them at 36-38° C. 
for 12-24 hours and then examine the growth in cover-glass preparations. The diphthe- 
ria organism if present should show: 
a. Characteristic appearance with Loeffler’s methylen blue. 
b. Positive Neisser stain. 
c. Positive Gram stain. 
