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Scientific Memoirs by
stratum of considerable thickness, with irregularly lobate margins and shining polished
surface ; colour at first ochreous, but gradually acquiring a strong burnt-sienna tint
elements at first consisting almost purely of short, straight rods, but in the later stages
a certain number assuming the form of large, well curved and often distinctly beaded
commas.
5. Growth in bouillon. —In neutralised media slow, and for a considerable time
unattended by distinct clouding of the medium ; forming a distinct pellicle, usually in
the form of isolated, white flocculi, but sometimes as a continuous thick stratum ; the
material in any case incoherent and tending to subside on any agitation ; no development
of purple on the addition of acids.
Form Є.
1. Growth in neutralised agar-agar media.—Occurring rapidly both superficially and
interstitially ; surface growth usually very thick, conspicuously, roughened and of a warm
ochreous tint, originally tenacious or ropey, but now invariably quite incoherent ;
elements resembling those of form β morphologically but ordinarily of relatively large size.
2. Growth in non-neutralised agar-agar media. —Solely superficial and at the outset
not quite so rapid as in the case of α, β and γ.
3. Growth in gelatine.—Liquefaction considerably retarded but by no means so
greatly so as in the case of β. (Plate 1, Fig. 3, b . Plate II, b, Figs. 1-8, Є.)
4. Growth on potatoes.—Occurs very rarely save in purely abortive fashion ; when
vigorous, giving rise to strata of very considerable thickness and firm consistence, of a
bright pink colour and ordinarily composed of short oval ele ments.
5. Growth in bouillon. —No distinctive features in neutralised media ; absent in
non-neutralised ones.
Form ζ.
1. Growth in neutralised agar-agar media. —Occurring rapidly both superficially
and interstitially; surface growth usually forming a smooth, polished stratum of highly
tenacious or ropey consistence ; elements consisting of rods, ordinarily of comparatively
small size and very deficient in curvature.
2. Growth in non-neutralised agar-agar media. —Solely confined to the surface,
and now so extremely retarded that mere traces of it are present at periods at which
in cultivations of most other forms the entire surface has been covered by a thick conti-
nuous stratum ; elements either coccoid or thick, almost straight rods. (Plate IV, Fig. 4.)
3. Growth in gelatine. —Phenomena of liquefaction entirely unlike those present
in cultures of any of the preceding forms due to its being confined to the surface of the
medium, so that the channel appears at first in the form of a very shallow saucer, and
then of a superficial stratum of fluid bounded beneath by the flat surface of the
undissolved portion ; progress of liquefaction relatively slow. (Plate I, Fig. 3, a . Plate II, b,
Figs 1-8,ζ .
4. Growth on potatoes.—Very rare save in purely abortive form ; when vigorous,
it, like that of the preceding form, is of a pink colour, but the colour is not so bright and
has a more or less yellowish tinge, and the growth is not so vigorous as in growths of that
form ; forming a comparatively thin, moist stratum and consisting of slender, straight
rods not unlike those present in many cultures on neutralised agar-agar media.
5. Growth in bouillon. —Shows no distinctive peculiarities where the medium is
neutralised ; entirely absent where it is not neutralised.