isms than as a single one. Indeed, Quincke has described three species, though they are not yet generally accepted.

The organism can be studied by extracting a hair and examining it in KOH or NaOH solution (20 per cent.), or by teasing a scutulum in the same medium and examining with a low power. Sections of the skin may also be made when possible.

The fungus resolves itself into mycelial threads and spores. The scutulum consists of masses of spores at the center and about the hair, with mycelia containing spores at the edges.

From the mycelium hypha are given off, the ends being knobbed or clavate.

The mycelial threads are highly refractile, contain granular protoplasm, and are of varying thickness. Sometimes the terminal hypha are simple, sometimes they fork, the ends are always clavate. The hypha give off buds at right angles along their course.

The spores are oval, doubly contoured, as a rule, but may be round or pointed and more or less polyhedral. They measure 3 to 8 μ in length and 3 to 4 u in breadth. They form the great central mass of the scutulum, which is the oldest part. Together with them one finds a number of detritus granules, fat-droplets, and occasional swollen epidermal cells.

Cultivation. The cultivation of the achorion is quite easy if care be used, for the central part of each scutulum contains pure cultures of the organism. The best method is

probably that of Kral,* which is as follows: "A good deal of the material from the scutula is rubbed up in a porcelain mortar dish with previously heated diatomaceous earth, with a porcelain pestle, without exerting too much pressure. Melted agar-agar tubes are then inoculated with two or three loopfuls of the crushed material and poured into Petri dishes. Greater dilution can be made if desired. The plates are examined after forty-eight hours.

Cultures may, however, be directly made with material from the center of a scutulum. Agar-agar should be used, as the cultures grow best at the body temperature. The young colonies that appear in forty-eight hours can easily be transplanted by fishing under a lens.

The best medium was found by Sabouraud to consist of maltose, 4; peptone, 2; fucus crispi, 1.5; water, 100.

As the colonies eventually become quite large it is recommended that, instead of tubes, they be made in Erlenmeyer flasks, the transplanted little colonies being placed at the center of the medium congealed upon the bottom of the flask. The appearance of the cultures varies considerably. Plaut gives two principal varieties: (1) The waxy type-a yellowish mass of a waxy character with radiating folds and a central elevation. As a rule no aërial hypha, but occasionally short aërial hypha.

(2) The downy type-this forms a white disk with a velvety or plush-like covering of white aërial hypha. Sometimes instead of white the color is yellowish or reddish. A marked dimple with a smaller elevation usually occurs in the middle, and there may be radial folds.

Pathogenesis. The micro-organism is pathogenic for mice, rabbits, cats, dogs, hens, and men, in all of whom typical scutula form. Scutulum formation has not been observed in guinea-pigs. The disease readily spreads from animal to animal by direct contact, and by indirect contact by the use of combs, hair-brushes, and similar objects. On account of its chronicity, its obstinacy, its disfigurement, and its transmissibility it is a dangerous disease, and one that requires prompt isolation of the patient and the utmost care for the prevention of contagion.

* See Plaut, in Kolle and Wassermann's "Pathogene Mikroörganismen," 1, p. 608.

BABES, 355, 368, 419, 474, 478, 479, Bernheim, 746

Bordet, 26, 120, 140, 141, 144, 146, Cadio, Gilbert, and Roger, 754