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632 Hansen, from disintegration, can be detected. By some authorities it is said to possess a gelatinous capsule. In common with Bacillus tuberculosis and Bacillus smegmæ it retains carbol-fuchsin stains after being treated with mineral acids. It may be distinguished from Bacillus tuberculosis by its staining more readily with cold weak solution of carbol fuchsin, and by being decolorized more easily with dilute acids; by the impossibility hitherto experienced of growing it on the usual culture media, and of successfully in-

Fig. 88.—Bacillus lepræ. x 1,000. (Muir and Ritchie.)

oculating it into man and the lower animals; by its tendency to occur in dense clusters and in greater numbers; and by its very generally being found inside cells or, according to Unna, in zooglœa masses in the lymphatic spaces.

Specimens of the bacillus can be procured readily by excising a portion of a leproma—a proceeding, in consequence of the absence of sensation in most tubercles, not usually much objected to by lepers; or they may be obtained by including a succulent leproma in a pile clamp, slowly screwing up the jaws of the instrument so as to drive out the blood,