348 OH NO. 



Table 4. — Types of cholera vibrios developing typical morphology — ^Continued. 



Series of 



tubes, 

 peptone 

 solution. 



Reaction of media. 



(3) "Helmon I." 



Turbidity. 



Morphology. 



1 



2 



3 



4 



Acid, 1. r-) per cent 



Acid, 1.0 per cent 



Acid, 0. 5 per cent 



Neutral 



^- 



+++ 

 + + 



± 



+ 



Very few straight forms. 



Slightly curved forms. 



Comma forms, numerous spirilla. 



Typical comma forms, no spirilla. 



Typical, spirilla. 



Typical, comma forms. 



Typical, comma forms. 



Short, curved and .some oval forms. 



Spherical forms. 



1 



5 



6 



7 



8 



9 



Alkaline, 0.5 per cent 



Alkaline, 1. per cent 



Alkaline. 1.5 per cent 



Alkaline. 2.0 per cent 



Alkaline, 2. 5 per cent 



Series of 



tubes, 



peptone 



solution. 



Reaction of media. 



(4) "Juan I." 



Turbidity. Morphology. 



1 



2 



3 



4 



5 



6 



7 



8 



9 



Acid, 1. 5 per cent 



Acid, 1. per cent 



Acid, 0. 5 per cent __ 



Neutral — 



+ 

 + ± 



+ + 

 ± 

 ± 



Very few thin, short rods. 



A few rods and a few oval forms. 



Curved rods. 



Rods slightly curved. 



Curved, rods and oval forms. 



Oval and spherical forms. 



Short, small forms. 



Not visible. 



Not visible. 



Alkaline, 0. 5 per cent 



Alkaline, 1.0 per cent 



Alkaline, 1.5 per cent 



Alkaline, 2. per cent 



Alkaline, 2. 5 per cent 



it is a striking fact that the reaction of the typical cholera stool gen- 

 erally agrees with the reaction of the peptone solution in which the 

 typical form of that strain of cholera vibrio occurs. I have examined 

 the reaction of 26 typical cholera stools in all of which cholera vibrios 

 were found, and I M^as able to ascertain that most of them (that is, 

 73 per cent) showed an alkaline reaction (the maximum correspond- 

 ing to 0.88 per cent nonnal caustic soda), while about 30 per cent were 

 acid (the highest degree of acidity equaling 1.24 per cent of normal 

 hydrochloric acid), and the rest (about 7 per cent) being neutral. 

 (See Table 5.) From one sample of 1.24 per cent acidity, the typical 

 vibrio form was not seen in 0.5 per cent alkaline peptone, but the 

 smear from the stool showed typical vibrios, and slightly thick and 

 short vibrios developed on 0.3 per cent acid peptone. The alkalinity 

 of a stool which contains cholera vibrios in almost pure culture usually 

 increases by standing a few days, and from these stools it is very 

 difficult to cultivate cholera vibrios in typical form in acid peptone 

 solution. 



