densely felted mycelium of a silvery-white colour, with a peripheral zone of irregularly moniliform threads with terminal chlamydospores cemented together by a dark brown interstitial substance.
The grains are found in the cellular tissue, always singly and within small cavities. Each grain is surrounded by enormous giant cells, and by epithelioid cells of all sizes, and is enclosed in a characteristic shell of connective tissue.
This kind of mycetoma appears to be more amenable to treatment. Bouffard's and Bovo's cases were radically cured by curettage. In Bovo's case a secondary extension to the groin lymphatics of tbe affected side had suggested the diagnosis of melano-sarcoma.
v. CLASSIC BLACK MYCETOMA
Caused by Madurella mycetomi (Laveran, 1902). This mycetoma has a very wide distribution. It has been observed in Italy, in Africa (Senegal, French Soudan), and in India.
The grain formed by Madurella, mycetomi is dark brown or black in colour. It measures 1 to 2 mm. in diameter, is hard and brittle; its surface is irregular and frequently presents pointed eminences which differentiate it from the larger and smooth grains of Aspergillus bouffardi. The grain is composed of white threads, always over 1 μ in diameter and attaining at times 8 to 10 μ., which secrete a dark brown substance that cements them together. The grain is first surrounded by giant cells, epithelioid cells, and numerous polynuclear cells, and shows numerous chlamydospores at the periphery. Then a thick capsule of fibrous connective tissue forms round it. This puts an end to the vegetation of the fungus, which passes into a resting stage and is converted into sclerotia, in which form it is eliminated. This was shown by Carter as early as 1860. The grains form rapidly within the tissues. Brumpt reports a case in which they were eliminated in large numbers one month after the commencement of the disease.
Each grain may become the centre of an active colony, which continues to 'extend, destroying the surrounding tissues, until arrested by a barrier of sclerosed tissue. Thus large tumours may be formed. In very old grains the mycelium presents cavities filled with numerous chlamydospores. Sometimes, on account of unfavourable conditions, certain lobes of the fungus separate from the rest of the colony and become independent grains. This mode of vegetation, characteristic of the species, gives to the lesions a typical rosette-like appearance.
vi. BRUMPT'S WHITE MYCETOMA
Caused by Indiella mansoni (Brumpt, 1906). This form was described from a specimen of Indian origin in the museum of the London School of Tropical Medicine.
The grains peculiar to this form are hard, white, and very small, varying in size between ⅛ and ¼ mm., and having
