Medical Officers of the Army of
India.
The failure of growth in Agar-agar media, and nutritive broth lasted so long that it
almost appeared as though a permanent variety had been established, and, had
not attempts at recovering the original form been persistently carried out, the
natural conclusion would have been that this had actually occurred. At length,
however, in the beginning of October, a tube which had been inoculated from a
potato set on . the 27th September, and in which the growth presented once again
the irregular outlines and detached islets characteristic of the primary cultiva-
tions, yielded a successful result. The growth was, however, very slow, and
solely confined to the surface, spreading gradually around the orifice, but never
appearing around the length of the needle-track.
From this time onwards, successful transfers continued to occur in cases
where Agar-agar medium was employed, but the growth in them continued to be
entirely limited to the surface, and transfers to nutritive broth were still persist-
ently unsuccessful. The growth in these cases of partial recovery of the
original properties was composed to a large extent of Comma-Bacilli, but only
a few of them presented normal appearances, the larger number continuing, as
in the growths on potatoes, to appear either as if composed of a series of beads,
or of two associated oval particles. Full resumption of original powers for
anaërobic growth in the substance of Agar-agar media, of liquefying gelatine,
and of growth in broth was first present in a cultivation which was set on the
8th of December, but has continued to manifest itself in all subsequent cultiva-
tions up to the present time. Even where the original properties are fully regained,
however, a certain amount of effect due to the influence of the medium continues
to manifest itself, for if two tubes of gelatine be simultaneously inoculated, one
from a potato cultivation, and the other from another gelatine . or Agar-agar
cultivation, an appreciable difference in the rate at which liquefactions of the
medium advances is recognisable, the process being appreciably slower, es-
pecially at first, wher ea potato cultivation has been the source of the inoculated
material. The cultivations on potatoes retain the same general characters which
they had during the period when transfer to the other media was impossible,
save that there is, perhaps, a more constant tendency to isleted growth, and
their microscopical characters remain apparently unaltered, but the growths in
common gelatine, Agar-agar, and broth media, present the characteristic features
of cultivations of the typical Commas of the species, and microscopically consist
of such bodies. The broth cultivations yield beautiful, strong purple within 24
hours, form tough, membranous, wrinkled pellicles, have the characteristic light
cloudiness, and the ordinary tendency to persistent evolution of bubbles of gas
after the addition of the acids, which will be presently alluded to in describing
the phenomena presented by broth cultivations of the ordinary series.
In attempting to account for this gradual resumption of original properties
in the potato cultivations, after they had, for such a prolonged period, lost
them in such important respects, it was at first supposed that the nature of the
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