Scientific Memoirs by
precise amount of the milk. In one case where the point was accurately deter
- m i n e d , t h e a m o u n t o f t h e f l u i d a d d e d t o t h e m i l k w a s e q u i v a l e n t t o a b o u t o n e
three-hundredth of its bulk. The fluid which was employed was in all cases crowded
with enormous numbers of healthy Comma-Bacilli, the amount of them being
indicated indirectly by the opalescent character of the fluid, and being directly
ascertained by means of cover-glass preparations, whilst their quality was
determined by observations of the results following their cultivation in various
sterilised media, such as Agar-Agar beef-juice gelatine and sterilised samples of
milk. The fluid was in all cases prepared alike, a small quantity of freshly steri
-lised solution of common salt being introduced into a tube-cultivation of Comma-
Bacilli of 24 or 48 hours' standing, and containing a great growth of the
organism diffused over the oblique surface of the medium. Thorough shaking
then sufficed to wash off the greater part of the growth and to diffuse the
Bacilli through the salt solution, which coincidently exchanged its previous
transparency for opalescence. A little of the opalescent fluid was then removed
by means of a freshly sterilised and calibrated pipette, and a single drop from
the latter added to the sample of milk under investigation.
This was contained in a sterilised and plugged tube, which was then set in
the incubator at 37° C., and subsequently examined from time to time. The exa
-mination dealt in the first place with the general phenomena of change manifest
- i n g t h e m s e l v e s i n t h e m i l k , a n d , s e c o n d l y , w i t h t h e e v i d e n c e a s t o t h e p e r s i s t e n t
presence and multiplication of the normal lacteal schizomycetes present in it
originally and of the inoculated Comma-Bacilli. The phenomena presenting
themselves in the inoculated specimens were compared with those occurring in
corresponding specimens of milk derived from the same primary sample, which
had not been inoculated, but which had otherwise been exposed to like con
-ditions.
In regard to the general changes manifesting themselves in the milk, the
inoculated specimens showed no appreciable differences from their non-inoculat
- e d c o m p e e r s , a n d t h e p r e s e n c e o f t h e C o m m a - B a c i l l i d i d n o t a p p e a r t o h a v e
interfered with the progress of the acid fermentation and coagulation normal
to ordinary samples of milk. Within the course of 24 hours coagulation had
occurred in every case, and the reaction had assumed various degrees of per
- m a n e n t a c i d i t y . S e p a r a t i o n o f t h e c o a g u l a a n d f l u i d h a d g e n e r a l l y b e g u n t o
occur, and in every case was fully carried out within 48 hours from the com
- m e n c e m e n t o f t h e e x p e r i m e n t , t h e a c i d i t y a t t h e s a m e t i m e b e c o m i n g v e r y
strongly pronounced.
The cultivations of the inoculated milk also showed nothing to distinguish
them from those derived from the fluid in its normal condition. An abundant
development of colonies of the common lacteal schizomycetes invariably
occurred within 24 hours in plate-cultivations of the milk which had been
set 24 hours subsequent to the inoculation of the latter, but in no case
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