PATHOGENIC BACTERIA.

day appear about the size of lentils, and are situated in
little depressions. Under the microscope they are of a
yellowish-brown color, are finely granular, and are sur-
rounded by a zone of sharply circumscribed liquefied
gelatin. Careful examination with a high power of the
microscope shows a rapid movement of the granules of
the colony.

In gelatin punctures the growth takes place rapidly
along the whole puncture, forming a stocking-shaped
liquefaction filled with cloudy fluid which does not pre-
cipitate rapidly ; a rather smeary, whitish mycoderma is
generally formed upon the surface. The much more ex-
tensive and more rapid liquefaction of the medium, the
wider top to the funnel-shaped liquefaction at the surface.

FIG. 86.—Spirillum of Finkler and Prior: gelatin puncture-cultures aged
forty-eight and sixty hours (Shakespeare).

the absence of the air-bubble, and the clouded nature of
the liquefied material, all serve to differentiate it from the
cholera spirillum.

Upon agar-agar the growth is also very rapid, and in
a short time the whole surface of the culture-medium is