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662 much less an ulcer. Formerly it was thought that the lower animals were not susceptible to yaws. Several observers, including Castellani, have now shown that monkeys, even of a low order, can be successfully inoculated. Rabbits are also susceptible to intratesticular and subcutaneous inoculations (Nicholls and Castelli).

Sequelæ.— Mention is often made of nodes, of gummatous - like thickenings, and of punched - out, serpiginous and lupoid ulcerations in connection with yaws. Many authorities regard all such phenomena as being generally the results of an independent, though concurrent, syphilitic or tubercular infection.

On the other hand, the peculiar character of the periosteal thickenings; the sabre-like bending of the tibiae as if from some process of rarefying osteitis often leading to spontaneous fracture; the similar distortions of the bones of the forearms; the chronic serpiginous ulcerations of the forearms and legs, which, subsequently cicatrizing, lead to constriction, and cause unsightly chronic œdematous swelling of the distal parts; the gumma-like lumps on arms and legs, and even on the lips; these morbid phenomena, often encountered in yaws countries, taken in conjunction with the nature of the parasitic cause of this disease, tend to the conclusion that these lesions are of the nature of tertiary sequelæ. (Figs. 91, 92.) The subject requires further observation and study. Gangosa; destructive ulcerous rhino-pharyngitis (Leys).— This disease, which has been regarded by some as a sequel of yaws, generally commences as an ulcer on the soft palate. Slowly spreading, it may make a clean sweep of the hard palate, of the soft parts, cartilages and bones of the nose, sparing the upper lip, which is left as a bridge across a great chasm, the floor of which is formed by the intact tongue. The disease may be arrested spontaneously at any period of its progress and long before so extensive a mutilation as that described has been effected; but it is always a long-standing and chronic affair and may linger as an indolent ulceration for years. As a rule, the larynx is spared; but, although