Medical Officers of the Army of India .
13
On commensalism as a factor in determining the growth of certain
species of Comma-Bacilli under special conditions.
In connection with the views which Buchner and Metchnikoff have latterly
adopted in regard to the importance of commensalism of comma-bacilli with
other schizomycete organisms within the digestive tract, as a factor regulating
the capacity of the former to give rise to the choleraic condition in the host-
organism ; and also, because, if vibrionic organisms be in any way causally re-
lated to the disease, the normal phenomena of seasonal fluctuations in the pre
- v a l e n c e o f t h e l a t t e r , e s p e c i a l l y w i t h i n e n d e m i c a r e a s , m a y c o n c e i v a b l y b e , t o
some extent at all events, determined by commensal fluctuations in the numbers
of the causative organisms in the environment, or to commensal alterations
in the nature of the products which they are capable of elaborating there, it
appears to be worth while to record an undoubted example of the influence of
commensalism in preserving the vitality and securing the multiplication of a
species of choleraic comma-bacillus which came under observation in the early
part of the current year.
In the end of December 1895, an isolated and very rapidly fatal case of
cholera occurred in the person of a European soldier in Fort William, and some
of the contents of the stomach and intestines were submitted to me for bacterio
- l o g i c a l i n v e s t i g a t i o n . W h e n r e c e i v e d , t h e s p e c i m e n c o n s i s t e d o f a t u r b i d , p a l e
pinkish fluid, full of adhesive gelatinous flakes. The reaction was primarily neu
- t r a l , b u t b e c a m e f i n a l l y a c i d a s t h e t e s t p a p e r d r i e d . T h e a d d i t i o n o f p u r e n i t r i c
acid occasioned no perceptible increase in the depth of the pink colouration.
Cover-glass preparation showed that the mucous flakes, in many places, con
-tained nearly pure cultivations of beautiful, highly curved comma-bacilli, of rela-
tively large size, mingled with large numbers of characteristic intestinal epithe
- l i a l c e l l s . A p l a t e c u l t u r e , w i t h i n t h e c o u r s e o f 2 4 h o u r s , y i e l d e d a n a p p a r e n t l y
pure cultivation of rather large colonies, many ranging up to 0.11" or more in
diameter, of coarsely granular, lumpy texture, and with irregularly lobulated
margins. The odour of the culture was strong and musty, and the constituent
elements of the colonies had the form of relatively thick, short, well-curved
comma-bacilli. Even after 48 hours' growth, the colonies failed to acquire any
pink tint when treated with 33 per cent. nitric acid, but, after the lapse of 72
hours, gave well marked pink. Subsequent plate sub-cultures from the series
of tube-cultures derived from the primary one, however, especially in cases where
they had been developed under the influence of temperatures of 37°C. in the
incubator, struck beautiful pink with the acid within the course of 48 hours.
The abbreviation of the period of growth necessary to secure the colour
reaction may have been partly determined by the influence of continued cul
- t u r e i n a g a r - a g a r m e d i a , f o r t h e r e c a n b e n o q u e s t i o n t h a t t h i s , i n t h e c a s e