M e d i c a l . O f f i c e r s
o ft
h e A r m y
.
o fI
n d i a .
forms present on the surface in approximately equal proportions. The first of
these presented a bluish yellow tint when the plate was viewed obliquely by trans-
mitted light.. They were of considerable diameter and were composed of a
densely adherent stratum of small, well formed Commas. The , second, when
examined in the same fashion, were of a pure blue tint, quite diffluent and
composed of relatively long, slender Commas. The third were more . prominent
than the others, of a yellow tint, diffluent and composed of very short, thick,
almost micrococcoid Commas, which were distinctly vacuolate and only faintly
stained when treated with Gentian-Violet.
The present species was that which occurred in the first form of colonies,
the two next species being present in the remaining.forms respectively.
The morphological characters of the elements vary considerably in relation
to different media and different. methods of cultivation. In all cases they agree
in being short and relatively thick. In common nutritive gelatine they very
closely resemble those of species , being short, thick, well curved and pointed.
In neutralised Agar-agar they present similar features in cases where the cultiva-
tion has been initiated with materials derived from the ordinary gelatine or Agar-
agar series of growths. In non-neutralised Agar-agar they sometimes appear to
be merely abnormally small, but in others they are nearly straight and approach
in character those which occur in the growth on potatoes, and frequently in
neutralised Agar-agar cultivations derived from such growth. On potatoes they
are as a rule only very slightly curved, and in many instances present themselves
as short, straight oval bodies. In cultivations of the growth on potatoes in
neutralised Agar-agar there is in some cases a rapid reversion to the normal
well-curved form, and in others a persistence, more or less pronounced, of the
straight one.
They liquefy gelatine mucn more slowly than species a, ß, and y, and form
an evenly tapering tube, owing to the solution taking place only slightly more
rapidly at the surface than along the course of the needle track. The growth
in neutralised Agar-agar is rapid both superficially and intersticially, and the
surface-growth is usually very thick. In some cases the surface-growth remains
quite smooth, and in others becomes irregular. As will be seen by a reference to
Table I, it is distinguished from the surface growths in corresponding cultivations
of the previous four species by the frequency with which it is very adhesive or
ropey. In cultivations conducted at the temperature of the laboratory during
the summer months, this character was almost invariably present, but since, the
onset of the cold season, it has, as a rule, been absent or only feebly developed.
The growth in non-neutralised Agar-agar is relatively rapid and entirely
confined to the surface of the medium.
It does not grow very readily on potatoes unless acclimatised to them as a
medium, but when successful cultivation takes place, the growth is at once dis-
tinguished on normal potatoes by, its thickness and bright pink color (vide
D 2
19