128 The Phiippine Journal of Science 1915 
the peptone solution a medium which would act not only as an 
enriching medium, but also as a selective one. The bile medium 
of Ottolenghi and the application of the principle of Dieudonné’s 
agar to liquid media as suggested by Kraus are particularly of 
note. The literature on this subject is not lacking in criticism 
in regard to those two media. Contradictory results have been 
obtained by various authors,” and the impression seems to prevail 
that the advantages attached to either one of these enriching 
media are so slight as not to warrant a substitution for the pep- 
tone solution. From the purely scientific standpoint the ten- 
dency is to cultivate bacteria on media of simple and uniform 
composition, while from the practical standpoint a reliable me- 
dium is desired which can be prepared with the least loss of time 
and with the least trouble. None of the substitutes exceeds the 
peptone solution in either of the requirements; besides, as will be 
seen later, their reliability under certain conditions is doubtful. 
Owing to the lack of uniformity in their composition, the media 
must be tested before use. 
CULTURAL EXPERIMENTS WITH THE CHOLERA VIBRIO AND BACTERIA 
ASSOCIATED IN CHOLERA STOOLS 
In a series of experiments I have used various enrichment 
media to compare their practical value—peptone solution of 
varying chemical reaction (NaOH, Na,CO,), Kraus’s medium, 
and the bile medium. Several instances of these comparative 
tests are given in the tables. 
The arrangement of the experiments is evident from the pro- 
tocols. Liquid stools were used. The stool specimens were 
thoroughly shaken before planting. The platinum loop was of 
uniform size (4 millimeters in diameter). 
Terms used in the protocols. 
= No cholera colonies present. 
= No growth at all. 
} Cholera colonies present. 
any few. Less than half a dozen. 
Few. About one dozen. 
Morethanafew. About 50. 
Numerous. About 200. 
Very numerous. More than 200. 
PROTOCOLS OF EXPERIMENTS 
One loopful of cholera feces was inoculated into each tube of enrichment 
medium. Streak cultures were made on agar plates. One loopful 
was transferred. 
* See references at the end of this paper. 
