Thrush is a disease of the mouth seen most often in children, and characterized by the presence of white patches upon the mucous membrane. It is caused by the thrush fungus, Oïdium albicans. When a bit from one of the patches is pressed out between a slide and cover and examined with a one-sixth objective, the fungus is seen to consist of a network of branching segmented hyphæ with numerous spores, both within the hyphæ and in the meshes between them (Fig. 122). The meshes also contain leukocytes, epithelial cells, and granular débris.
| FIG. 122.—Thrush fungus (Oïdium albicans) (Jakob). |
| FIG. 123.—Bacillus diphtheriæ, from culture on blood-serum. X1000 (Fränkel and Pfeiffer). |
Acute pseudomembranous inflammations, which occur chiefly upon the tonsils and nasopharynx, are generally caused by the diphtheria bacillus, but may result from streptococcic infection. In many cases diphtheria bacilli can be demonstrated in smears made from the membrane and stained with Löffler's methylene-blue or 2 per cent. aqueous solution of methyl-green. They are straight or curved rods, which vary markedly in size and outline, and stain very irregularly (Fig. 123). A characteristic form is a palely tinted rod with several deeply stained granules (metachromatic bodies), or with one such granule at each end. They stain by Gram's method. It is generally necessary, and always safer, to make a culture upon blood-serum, incubate for twelve hours, and examine smears from the growth.
| FIG. 124.—Bacillus and spirillum of Vincent, from case of ulcerative stomatitis. Stained (obj. one-twelfth oil-immersion; X1000) (Boston). |
Vincent's angina is a chronic pseudomembranous and ulcerative inflammation of pharynx and tonsils. It is probably caused by two micro-organisms living in symbiosis—one a fusiform bacillus, the other a long spirillum (Fig. 124). They can readily be demonstrated in smears stained with Löffler's methylene-blue. The bacillus is spindle shaped, more or less pointed at the ends, and about 6 to 12 µ long. The spirillum is a very slender, wavy thread, about 30 to 40 µ long.
Tuberculous ulcerations of mouth and pharynx can generally be diagnosed from curetings made after careful cleansing of the surface. The curetings are well rubbed between slide and cover, and the smears thus made are dried, fixed, and stained for tubercle bacilli. Since there is much danger of contamination from tuberculous sputum, the presence of tubercle bacilli is significant only in proportion to the thoroughness with which the ulcer was cleansed. The diagnosis is certain when the bacilli are found within groups of cells which have not been disassociated in making the smears.
THE EYE
| FIG. 125.—Conjunctival secretion from acute contagious conjunctivitis; polynuclear leukocytes with the bacillus of Weeks; P, phagocyte containing bacillus of Weeks (one-twelfth oil-immersion; ocular iii) (Morax). |