Medical Officers of the Army of India.
3 1
white or faintly greenish stratum of absolutely diffluent consistence ; interstitial growth
unattended by any appreciable darkening in the colour of the medium, and almost
invariably by an increased pallor in it ; growths possessing a peculiar urinous or
herring-pickle odour ; elements consisting invariably of slender rods ; the majority
straight and only a limited number showing any decided curvature, very frequently
distinguished by the relatively light colour which they acquire from staining re-agents.
2. Growth in non-neutralised agar-agar media. —Distinguished by the maximal ra-
pidity with which it extends over the surface, and by the fact that it occurs in appreciable
amount along the entire course of the track of the needle in stable-cultures ; elements
consisting of rods like those in neutralised agar-agar media, but ordinarily of exceptionally
large size. (Plate IV, Fig. 7.)
3. Growth in common nutrient gelatine media. —Distinguished from that of every
other form capable of causing liquefaction by the extreme slowness with which solution
occurs, so that, at a time when complete solution of the medium is present in tubes con-
taining even the least solvent of the other forms, mere traces of liquefaction are fre-
quently present in connection with it ; liquefying power diminished under prolonged
culture in agar-agar media. (Plate 1, Fig. 5, b . Plate III, b , Figs. λ .)
4. Growth in potatoes.—Occurs freely and almost invariably ; no evidence of any
appreciable loss of capacity for growth in connection with very prolonged cultivation in
agar-agar media ; forming comparatively thin, dryish, pale ochreous expansions over the
surface ; surrounding surface of the potato from the outset showing a brownish halo and
ultimately becoming of a strong raw umber tint ; cultivations invariably having a peculiar
strong, bitter-sweet odour ; elements presenting almost the same morphological charac-
ters as those in neutralised agar-agar media. (Plate IV, Figs. 9, a and b .)
5. Cultivation in bouillon. —Characterised in cases where the medium is neutralised
by the extreme rapidity with which dense clouding occurs throughout the fluid, which at
the same time acquires a peculiar whitish tinge, and by very great delay in the appearance
of any traces of a pellicle ; the addition of acids followed by a relatively limited develop-
ment of purple, and the colour being peculiarly distributed in a superficial and basal
stratum, leaving an intermediate zone almost unaffected ; in cases where the medium is
non-neutralised, the growth is attended by precisely similar phenomena, save that there
is a complete failure in the development of any purple on the addition of acids.
Form µ.
1. Growth in neutralised agar-agar media.—Occurring rapidly both superficially and
interstitially ; superficially forming a thick stratum, ordinarily somewhat roughened and
diffluent or only very faintly adhesive in consistence ; elements consisting of very thick
short commas, ordinarily rather defective in curvature, and with a great tendency to aggre-
gation so as to form dense clumps.
2. Growth in non-neutralised agar-agar media. —Rapid but purely superficial ; ele-
ments of the same character as those in cultivations on neutralised media.
3. Growth in common nutrient gelatine.—Liquefaction taking place with moderate
rapidity : the channel usually presenting a peculiar napiform outline for some time, due to
the process of solution not taking place so rapidly on the surface of the medium or in the
deeper portion of the track of the needle as it does in the intermediate area. (Plate I,
Fig. 6, a . Plate III, b, Figs. µ.)
4. Growth in potatoes.— Only very rarely occurring with vigour, but when doing so