Medical Officers of the Army of India.
Plate III, b, we have a corresponding series of drawings of another set of tube-
cultures of the nine forms which have been longest subject to the influence of like
common conditions. The remaining figures in Plate III and all those in Plate
II illustrate the characters of the growths presented by the forms which were
photographed at different periods during the time in which they have been in con-
tinuous cultivation in agar-agar media. For forms α, β, ε,ζ,η and θ there are
figures illustrating the characters of the growths in seven distinct series of tube
cultures, whilst for forms γ, ι, a n d
κ w e h a v e i l l u s t r a t i o n s o f s i x , f o r f o r m sλ
a n d
η of four, and for forms ζ and o of two distinct series of cultures. The defective
number of i ustrations in the case of forms y, ι a n d
κ i s o w i n g t o t h e d r a w i n g s
of them for a particular set of cultures having been mislaid, and the small num-
ber of figures of the remaining forms is accounted for by the comparatively
short time that they have been under cultivation and the fact that it is only
during a period of a few weeks in the cold season that gelatine-cultures can be
satisfactorily carried out in Calcutta. In the case of those forms whic have
been longest under cultivation, the figures illustrate the characters of growth for
three successive years, in the case of the remaining forms cultures for two years
or for one year only are illustrated. The drawings have been numbered so as
to facilitate as far as possible the comparison of the characters presented by
all cultures which were conducted simultaneously. All the drawings bearing
the same numbers represent tubes containing portions of one and the same
sample of the nutrient medium and inoculated and figured simultaneously. The
series of figures which are numbered I are copies of drawings from photographic
negatives of cultures from which, although they were too weak to yield satisfac-
tory prints, tracings could readily be obtained. All the other figures are repro-
ductions of carefully measured pencil drawings taken direct from the cultures
themselves. The gelatine which was employed in these cultures was not always
alike, for in series I, 2, 4, and 5 it consisted of Heinrich's " gold label" flake-
gelatine and in the rest of Nelson's "photographic gelatine." In both cases the
medium contained Io per cent. of gelatine, but it was of considerably greater
density where the "gold label " material was employed than where it was replaced
by the photographic gelatine.
When we compare the figures illustrating each form separately, we find
that they indicate that continued cultivation in agar–agar media has in some
cases been attended by a great increase, in others by a great decrease, and
in still others by no appreciable alteration in capacity for liquefying gelatine.
In the case of form ι ,
l i q u e f y i n g p o w e r h a s m a n i f e s t l y u n d e r g o n e a g r e a t
increase; in form β it has as conspicuously decreased and in ,forms γ, ε and
it has undergone little change of any kind. In the case of form η it has
somewhat decreased and the process of liquefaction has at the same time
become conspicuously modified, seeing that primarily it occurred almost simulta-
neously along the entire length of the needle-track so as to lead to the formation
19
D 2'