PRACTICAL EXPERIENCE WITH SOME ENRICHING MEDIA 
RECOMMENDED FOR BACTERIOLOGICAL DIAGNOSIS 
OF ASIATIC CHOLERA * 
By OTTo ScHOBL 
(From the Biological Laboratory, Bureau of Science, Manila, P. I.) 
It appears from the literature as though the classical Koch- 
Durham peptone solution has not always given satisfactory 
results. Ohno (1), in this laboratory, made a thorough study of 
the relation between the chemical reaction of the culture medium 
and the morphology of cholera vibrio. Led by the experience 
that a sudden change of chemical reaction of the medium in which 
cholera vibrio is growing causes change in morphology, he tested 
the reaction of a series of cholera feces. As a consequence of 
this study Ohno advises the use of peptone of three different 
reactions which correspond to the reaction of the cholera feces: 
namely, 0, 3, -0, 5, -1, 3. The significance of this phenomenon in 
relation to our method of examinations is evident, as the presence 
of vibrios in the peptone culture was used as an indicator in the 
search for contact carriers, and only those samples were plated 
which contained vibrios. The objection may be made that owing 
to the difference between the reaction of the feeces and that of the 
peptone medium the cholera vibrios assumed an atypical form and 
remained unrecognized. It is an actual fact that cholera vibrios 
will lose the typical vibrio shape if transferred from acid to alka- 
line medium or vice versa, but such a change is not a permanent 
one, and the new generations, which follow in rapid succession, 
adapt themselves to the new conditions and soon appear in 
typical vibrio shape. This is particularly true of liquid media, 
provided the reaction remains within the limits of maximal 
acidity and maximal alkalinity. 
Numerous stools from patients, convalescents, and suspects 
submitted by the quarantine hospital, which were all examined 
by hanging drop, enrichment process, and Dieudonné’s plates, 
showed that in every instance in which cholera vibrios were 
found on the plates motile vibrios were present in the corre- 
sponding peptone culture after an incubation of from twelve to 
eighteen hours. All liquid stools from cholera patients were of 
pronounced alkaline reaction to litmus paper. 
Several suggestions recently have been made to substitute for 
*Received for publication December 28, 1914. 
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