620 TRICHOMYCETES, ACTINOMYCETES, HYPHOMYCETES 
in this respect from the pseiidomembrane of diphtheria and from the 
gray throat of scorbutus. The plaque is made up of epithehal cells 
overgrown with the organism. The lesion may spread to the larynx 
and esophagus and lead to a generalized fatal infection. Usually, 
however, the prognosis is favorable. 
The organism, Oidium albicans, was described by Langenbeck in 
1839, but it was first successfully cultured by Grawitz in 1871. The 
classification of Oidium albicans is not clear, for the organism grows 
both as a yeast and produces mycelia and spores. The yeast-like 
cells are oval or round, measuring about 4 to 6 microns in diameter, 
and they frequently form buds precisely like true yeasts. They 
stain mahogany-browii with strong Gram's solution. The mycelia 
are doubly contoured and form chlamydospores. If a bit of the 
membrane be macerated in a drop of acetic acid the epithelial cells 
are cleared and the parasite is readily observed. Two distinct types 
are recognizable in gelatin cultures, one of which liquefies the medium, 
the other does not. In solid media yeast-cell formation predominates 
and many of the cells are observed to bud; in fluid media mycelia 
are produced and spore-formation usually occurs after several days' 
incubation. The spores— chlamydospores— usually enlarge and develop 
into filaments when they are transplanted into fresh media. The 
organism is not uncommon in the air. 
The organism does not produce thrush when introduced into experi- 
mental animals, but it may cause a generalized thrush mycosis when 
injected intravenously in rabbits. 
Aspergillus if ?/com.— Aspergillus fumigatus occasionally incites a 
disease of the lungs and bronchi in birds and rarely in man. The 
organism penetrates to the alveoli and the mycelia and spores may 
be demonstrated in sections of the lungs in fatal cases. It also has 
been found rarely in middle-ear infections and in the naso-pharynx. 
The mold grows readily upon ordinary media, and the colonies, 
after several days, become dark green in color. The organism belongs 
to the genus Aspergillus, w^hich is widely distributed in damp cellars 
and upon food. Microscopically, aerial hypha? arise from the fila- 
mentous mycelium, whose distal ends are swollen into club-shape 
masses of undivided sterigmata, from which chains of conidia arise. 
The conidia are spherical, greenish, and measure about 3 microns in 
diameter. It is differentiated from many of the aspergilli by its green 
color, other members of the group exliibiting black, brown and other 
colored colonies. 
Rabbits, guinea-pigs and pigeons are susceptible to infection with 
Aspergillus fumigatus. The lesions produced resemble tubercles some- 
what on superficial examination, but microscopic examination always 
reveals the mycelium and spores. 
Sporotrichosis.— The disease known as sporotrichosis was first 
described by Schenck^ and later by Hektoen and Perkins.^ The 
1 Johns Hopkins Hosp. Bull., 1898, 9, 286. = Jour. Exp. Med., 1900, 5, 77. 
