forms such as sclerotia and chlamydospores, but also characteristic spore apparatus (Aspergillus nidulans, A. bouffardi). The species are as follows:—
i. ACTINOMYCOTIC MYCETOMA
Caused by the ray -fungus, Discom^ces bovis (Harz, 1877). Actinomycosis has a world-wide distribution and is a common disease of cattle. It occurs also in hogs. In men it may attack the extremities, giving rise to a tumour clinically indistinguishable from other kinds of mycetoma, or it may develop in the jaw, the tongue, lungs, liver, brain; and occasionally the primary lesion may be followed by metastases in all parts of the body.
The fungus of actinomycosis develops equally well in most tissues. It destroys bone by erosion and spares only nerves and tendons. The pus from the affected region contains small yellowish granules ("sulphur grains") of irregular shape, attaining at most 0'75 mm. in diameter. They are soft and consist of an inextricable felted mass of inycelia. The threads are radially arranged at the periphery of the grain, and their free extremity widens into a bulbous, club-like termination (10-20 μ. long by 8-10 μ wide). These clubbed ends have been looked upon by several authors as forms of degeneration. Brumpt points out that they consist of young, active protoplasm, and holds that they are functionally hypertrophied while elaborating food for the colony. In old grains the clubs disappear, their protoplasm being utilized in the formation of spores.
This fungus gives rise to ramified sinuses which extend in all directions, opening at the surface by numerous vents. The sinuses are surrounded by a thick fibrous sheath of connective tissue. The centre of the largest tunnels is softened, the youngest grains being at the periphery surrounded by polynuclear cells and almost in contact with the sclerosed tissues which separate the cavities and sinuses.
The parasite has been successfully cultivated, and the disease has been inoculated both with the natural and the artificially grown organism.
Discomyces bovis lives saprophytically on certain plants. It has been found on the spikelets of cereals ('Hordeum murmium L., Phleum pratense L., etc.), and is therefore probably inoculated through the skin or mucous membranes in the same way as the fungi which give rise to other kinds of mycetoma.
The diagnosis of the disease from tertiary syphilis and bone tuberculosis rests on the characteristic grains present in the pus.
The disease is progressive and of grave import. The treatment is largely surgical. In early cases iodide of potassium in doses of from 40 to 60 grains daily has proved advantageous, and in some cases even curative.
