Medical Officers of the Army of India. 2 7
2. Growth in non-neutralised agar-agar media. — S o l e l y s u p e r f i c i a l ; n o t q u i t e s o
rapid as that of form a ; elements retaining the same form as those in neutralised
media, but somewhat smaller than they ordinarily are there.
3. Growth. in common gelatine media.— P r o c e s s o f l i q u e f a c t i o n n o w e x t r e m e l y r e t a r d e d
and accompanied by relatively large multiplication of elements. (Plate I, Fig. 1, b . Plate
II, a , Figs. 1-8 β.)
4. Growth on potatoes —Generally absent or more or less abortive and consisting of
deformed elements, but occasionally extremely vigorous and giving rise to thick, soft, bright
yellow strata, composed of almost micrococcoid elements and usually spreading with a
peculiar, discontinuous margin.
5. Growth in bouillon.—No definitely distinctive phenomena present in neutralised
bouillon ; incapable of growth where the medium is non-neutralised.
Form γ
1.
Growth in neutralised agar-agar media.— S u p e r f i c i a l g r o w t h r a p i d a n d a b u n d a n t
interstitial growth now invariably retarded and partial. The superficial growth now
almost invariably tenacious and in some cases almost ropey. Elements of the growth
slender, well curved and pointed, non-aggregant commas. (Plate IV, Fig. 3.)
2. Growth in non-neutralised agar-agar media. —Purely superficial and composed
of elements closely resembling those normal to form β in neutralised media.
3. Growth in common gelatine.— L i q u e f a c t i o n o c c u r r i n g w i t h m o d e r a t e r a p i d i t y a n d
giving rise to the formation of a tapering channel. Solution attended by very consider-
able multiplication of elements and consequently by copious deposit ; channel of liquefac-
tion not showing the transparency and fine dotting peculiar to that in the case of form
α , and being much more rapidly formed than that in the case of form β. (Plate I, Fig, 2, a.
Plate II, a, Figs. 1-8, γ.)
4. Growth on potatoes.— T a k i n g p l a c e v e r y r a r e l y s a v e i n a b o r t i v e a n d i n v o l u t e d
fashion. Where vigorous, giving rise to the formation of a thin brownish-ochre, thalloid
expansions, consisting of slender commas, like those in growths in neutralised agar-agar
media, but frequently associated to form vibrionic filaments.
5. Growth in bouillon.—No distinctive features in cases where the medium is neu-
tralised. In non-neutralised bouillon it takes place slowly and solely on the surface of the
medium, and ultimately gives rise to the formation of a thin, imperfect pellicle consist-
ing of elements similar to those present in the growths on non-neutralised agar-agar
media.
Form δ.
1. Growth in neutralised agar-agar media.— E n t i r e l y , l i m i t e d t o t h e s u r f a c e o f t h e
medium, where it forms a pure white or somewhat greenish, polished stratum, usually quite
diffluent, but occasionally tenacious or ropey ; elements consisting of rods of consi
-derable size and ordinarily very deficient in curvature, but sometimes well curved and
associated in vibrionic filaments of considerable length.
2. Growth in non-neutralised agar-agar media. — A l s o p u r e l y s u p e r f i c i a l ; f a i r l y r a p i d
and consisting of elements which are frequently much altered in form, fusiform or plano-
convex, and almost invariably wanting in appreciable curvature.
3. Growth in common gelatine media. —Greatly retarded, purely, superficial and
unattended by any liquefaction.
4. Growth on potatoes.—Rapid and certain, giving rise to the formation of aE 2
E2