REACTION OF CULTURE MEDIA. 



347 



original form of the strain^ is^ I believe, a distinct aid and advance 

 in the bacteriological diagnosis of cholera and therefore will be of 

 assistance in the suppression of a cholera epidemic. 



Prom my investigations it would appear that the different strains of 

 the cholera vibrio may be arranged, with reference to their resistance 

 to acid and alkali, into four groups : 



1. Cholera vibrios resistant to acid solutions but not resistant to 

 alkaline ones. 



2. Cholera vibrios resistant to alkaline solutions but not resistant 

 to acid ones. 



3. Cholera vibrios resistant to both alkaline and acid solutions. 



4. Cholera vibrios not resistant to either alkaline or acid solutions. 

 By resistance is meant the power of the organism to grow and to 



multiply in the culture medium in question in a typical form. 



Table 4. — Types of cholera vibrios developing typical morphology, (1) in highly 

 alkaline media, {2) in acid media, (3) in both alkaline and acid media, {4) in 

 neutral media. 



Series of 



tubes. 



peptone 



solution. 



Reaction of media. 



(1) "Hoffman." 



Turbidity. 



Morphology. 



1 



2 



s 



4 



5 



6 



7 



8 



9 



Acid, 1.5 per cent 



Acid, 1. per cent 



Acid, 0. 5 per cent 



Neutral 



+ + + + 

 + 

 + 

 ±? 

 _? 



Not visible. 



Not visible. 



Not visible. 



Not visible. 



Bacillary form, some slightly curved, 



Thick and short, with slight curve. 



Typical comma forms. 



Spherical forms. 



Few spherical forms. 



Alkaline, 0. 5 per cent 



Alkaline, 1. per cent 



Alkaline, 1. 5 per cent 



Alkaline, 2. per cent 



Alkaline, 2.5 per cent 



Series of 



tubes, 



peptone 



solution. 



Reaction of media. 



(2) "Felix 11." 



Turbidity, 



Morphology. 



1 



2.. 



3 



4 



5 



6 



7 



8 



9 



Acid, 1.5 per cent 



Acid, 1.0 per cent 



Acid, 0. 5 per cent 



Neutral 



Alkaline, 0. 5 per cent 



Alkaline, 1.0 per cent 



Alkaline, 1. 5 per cent 



Alkaline, 2. per cent 



Alkaline, 2.5 per cent 



+ 



+ + 

 + + + 

 H- + H- 



-r 

 ± 

 ±? 



Half in straight form, half in curved form, 



size small. 

 Half in straight form, half in curved form, 



size small. 

 Mo.stly typical comma forms. 

 Organisms thick and .short, mostly of oval form. 

 Thicker and shorter, a few curved forms, the 



majority like cocci. 

 Oval or coccus forms. 

 Spherical forms. 

 Spherical forms. 

 Very few spherical form.s. 



