322 WATER HYGIENE 
with a Petri dish to prevent evaporation. Allow to stand for fifteen to 
twenty minutes. At the end of this time, stain and examine for clump- 
ing of the bacteria. 
Examine both slides for agglutination of the bacteria. 
Isolation of Microspira Cholerze from Water; Metschnokoff’s 
Method after Besson. Prepare a series of flasks and add 200 c.c. of 
the water under examination. To each flask add the following solution: 
Water 2.0... cee cee eee eee eae 50 c.c. 
Peptone.. oo. eee eee eee ees 2 gms. 
Common salt... 0... 0.0.0.0 c eee eee ee 2 gms. 
Gelatin.. 2 1... 0... ee. Lobe eens 4 gms. 
Sodium carbonate... .... Sufficient to make alkalin 
Sterilize this in the autoclave. Then add 150 c.c. of the water under 
examination and incubate at 37° C. If the water contains microspira 
a thin film will form on the surface in about cight hours. This film 
should then be examined under the microscope and if microspira are 
present they must be proven to be the pathogenic Microspira cholere. 
Besson gives the following “ classical characteristics of the M. cholere.” 
1. Characteristic appearance on gelatin plates and in gelatin stab. 
2. The presence of and the number of flagella. 
3. The nitroso-indol reaction in pepton water. 
4. Virulence for guinea pigs. | 
5. The immunity reaction (Pfeiffer’s reaction). 
6. Agglutination by anti-cholera serum. 
The agglutination reaction is probably the most reliable since this 
is quite specific. Besson mentions that the other characteristics of 
Microspira cholere are not fixed and are thus of little use in identifying 
a suspected organism. 
The Cholera-red Reaction. This is a reliable test for the diagnosis 
of Microspira cholere. Not‘many other organisms. The test is carried 
out by adding a little sulphuric acid to a broth culture of the organism. 
A red color results due to the presence of both indol and nitrites which 
are formed by the organism. Some care must be used in controlling 
the factors involved in the test. The pepton must be proven to yield 
the test when a known organism is used. The cholera-red test is of 
much value in identifying this organism in water. 
Detection and Isolation of Bacillus Anthracis from Water. Pasteur 
used the resistance of the spores as a means of isolating the bacillus from 
different substances. Heat a small quantity of the witer in » water 
bath for twenty minutes at 80-85° C. At the e: uw, make 
