tremely vascular. The mycelial or filamentous mass occupies the center of an area of degeneration, where it can be beautifully demonstrated by the use of appropriate stains, Gram's and Weigert's methods being excellent for

Fig. 271.-Melanoid form of mycetoma. Section showing black granules and general features of the lesions as they appear under a low-magnifying power. Zeiss a2 (James H. Wright).

Fig. 272.-Melanoid form of mycetoma. showing structure and appearance of the hyphæ of the mycelium obtained from the granules. Zeiss apochromat; 4 mm. (James H. Wright).

the purpose. The tissue surrounding the nodes is infiltrated with small round cells. Tne youngest nodules consist of granulation-tissue, whose development is checked by early coagulation-necrosis. Giant-cells are few.

Not infrequently small hemorrhages occur from the ulcers and sinuses of the diseased tissues; the hemorrhages can be explained by the abundance of small blood-vessels in the diseased tissue.

Fig. 273. Melanoid form of mycetoma. Two bouillon cultures showing the powder-puff ball appearance. In one the black granule is seen in the center of the growth (James H. Wright).

Potato culture of the

Fig. 274.-Melanoid form of mycetoma. hyphomycete obtained from the granules. The black globules are composed of a dark brown fluid (James H. Wright).

The Melanoid Form of mycetoma has been carefully investigated by Wright* and appears to depend upon an entirely different micro-organism properly classed among the * "Journal of Experimental Medicine," vol. III, 1898, p. 421.

hyphomycetes. It is probably identical with the organism described by Boyce and Surveyor.

In the case studied, Wright found the diseased tissues, consisting of several of the pads of the toes, to be either translucent and myxomatous or yellowish and necrotic in appearance. The black granules were embedded in the tissue and appeared mulberry-like and less than 1 mm. in diameter. They were firm, and when enucleated and pressed between cover and slide did not crush. Only after digestion with a solution of caustic potash and careful teasing could the granules be resolved into the hyphæ of the mold. The central part of the granule formed a reticulum, with radiating, somewhat clavate elements projecting from it.

In sections of tissue it was found possible to stain the fungus with Gram's and Weigert's stains, though prolonged washing removed most of the dye.

Cultural Characteristics.-Enucleated granules carefully washed in sterile bouillon and then planted upon agar-agar afforded cultures of the mold in 25 out of 65 attempts.

The growth began in five or six days, appearing on solid media as a tuft of delicate whitish filaments, springing from the black grain, and in a few days covering the entire surface of the medium with a whitish or pale brown felt-work. Upon potato this felt-work supports drops of brownish fluid. The long branched hyphæ thus formed were from 3 to 8 in diameter, with transverse septa in the younger The older hyphae were swollen at the ends. No buds were observed. No fruit organs were detected. In fluid media the filaments radiated from the central grain with the formation of a kind of puff-ball. Eventually the whole medium becomes filled with mycelia and a definite surface growth forms.

ones.

The general characteristics of the fungus are well shown in the accompanying illustrations from Wright's paper.

52

CHAPTER XXXV.

BLASTOMYCOSIS.

BLASTOMYCES DERMATITIDIS (GILCHRIST AND STOKES).

THE first case in which yeasts or blastomycetes were definitely connected with disease seems to have been published by Busse.* He observed a case of tibial abscess in a woman thirty-one years of age, who died about a year after coming under observation. Postmortem examination showed numbers of broken-down nodular formations upon the bones, and in the spleen, kidneys, and lungs. In all of these lesions he found, and from them he cultivated, an yeast, which, when introduced in pure culture into animals-mice and ratsproved infective for them. He called the organism Saccharomyces hominis, and the affection in which it was found "Saccharomycosis hominis."

In May, 1904, three months before the appearance of Busse's paper, Gilchrist exhibited to the American Dermatological Association in Washington microscopic sections from a case of cutaneous disease in which peculiar bodies, recognized as plant forms, were found. After the appearance of Busse's papers, Gilchrist† more fully described and illustrated his findings, calling the lesions "blastomycetic dermatitis." Though much work upon pathogenic blastomycetes has been published and pathogenic forms of these micro-organisms have been described by Sanfelice, ‡ by Rabinowitsch, § and others, the chief and almost the sole form in which these infections make their appearance is a dermal infection known as "blastomycetic dermatitis."

The infection usually begins with the formation of a papule upon the face or one of the extremities, which suppurates and evacuates minute quantities of viscid pus. The lesion crusts

* "Centralbl. f. Bakt. u. Parasitenk.," 1894, XVI, 175. "Johns Hopkins Hospital Reports," 1, 269, 291.

"Centralbl. f. Bakt. u. Parasitenk.," 1895, XVII, 113, 625; XVIII, 521;

XX, 219.

§ "Zeitschrift für Hygiene," etc., 1896, XXI, II.

and begins to heal, but at the periphery new and usually minute foci of suppuration occur, so that while the original lesion tends to heal very slowly, with much cicatricial formation, it is always spreading. The progress is usually slow, and Gilchrist's first case spread only two inches in four years.

Though the progress is slow, it is sure, and there is no tendency to spontaneous recovery in most cases, nor is the condition modified by treatment. The patients may die from intercurrent disease or from a generalization of the blastomycetic infection, which not infrequently happens.

After the work of Gilchrist had made clear the symptomatology and parasitology of the disease, a number of other

cases were reported, and Ricketts* published an excellent and lengthy summary of all the cases with references to all of the literature up to that date. Another very interesting paper by Montgomery, † published in 1902, contains a splendid atlas of photographs of the various lesions and of the cultures.

In addition to the cutaneous blastomycosis, a second form is also occasionally seen, and is known as Coccidioidal granuloma. It seems to have been first reported by Posadas and Wernicke and has been carefully studied by Ophüls. § In

* "Jour. Med. Research," 1901, 1, 373.

†"Jour. Amer. Med. Assoc.," June 7, 1902, 1, 1486.

"Jour. de Microorganismen," 1891, XV, 14.

§ "Jour. Experimental Medicine," 1905, VI, 443. Ophüls and Moffit, "Phila, Med. Jour.," 1900, V, 1471.