HYPHOMYCETES 619 
brownish— after prolonged cultivation. Plant^ states that there are 
two varieties of Trichophyton tonsurans, one, less common, produc- 
ing relati\ely large spores, the other producing smaller spores. Guinea- 
pigs may be successfully infected with cultures of the organisms 
grown on artificial media ; a small area on the back is e])ilated and the 
culture rubbed in. The lesions are self-limited and usually heal spon- 
taneously after a few weeks. Strickler' has used a polyvalent vaccine 
for ringworm with success. Several injections at intervals of about 
five days are necessary in obstinate cases. 
Pityriasis l>mco/or. — Pityriasis versicolor is a disease of the 
epidermis which differs from favus and ringworm anatomically in 
that the infecting organisms neither penetrate the deeper layers of 
the skin, nor do they cause any noteworthy alterations in the skin or 
hair. Usually the epidermis of the chest, abdomen, joints and axilla 
are involved, rarely the neck. The disease is observed in the uncleanly 
and particularly in those who perspire freely. The tuberculous and 
diabetic are not infrequently infected. The disease is characterized 
by the development of light browii or yellow patches which are not 
noticeably raised above the surrounding surface; these patches are 
irregular in outline and tend to spread and coalesce. 
The inciting organism, Microsporon furfur, was described in 1846 
by Eichstedt. The organism resembles the Achorion schonleinii 
rather closely. It occurs in abundance in the scales where the relatively 
short, thick, septate hyphae surrounded by large groups of spores 
are quite characteristic. The hypha? measure from 3 to 4 microns 
in diameter and the spores are frequently observed to be enclosed in 
a spirally coiled covering. They measure about 3 to 6 microns in 
diameter. 
Cultivation of the organism upon artificial media is accomplished 
with difficulty and glycerin media are best adapted for this purpose. 
The colonies are very minute— 0.5 to 1 mm. in diameter. They are 
white or brownish and tend to spread over the medium. The hyphse 
are usually definitely curved and the ends are somewhat club-shaped. 
The spores occur in masses very similar in arrangement to those 
observed in the scale itself. Cultures rubbed into an epilated area on 
the back of rabbits may induce the characteristic colored patches if 
the inoculated area is protected with a thick covering to induce 
hyperemia. 
Thrush or Soor.— Thrush is primarily a localized disease of the 
mouth, occurring chiefly in weakly children. It has also been found 
in the vagina of pregnant women and in adults suft'ering from severe 
nutritional disturbances, diabetes and typhoid fever. The early 
lesion is a small white plaque which has a velvety appearance, differing 
* Plant removes a hair to a sterile moist chamber, seals the cover-glass with melted 
paraffin and incubates for several days. When the spores have germinated the mycelia 
may be removed and cultivated upon agar or gelatin. 
2 Jour. Cutan. Dis., 1915, p. 161. 
