406 m'laughlin and whitmore. 



We have Jt'ound no media which would differentiate cholera from non- 

 cholera vibrios, although we have had an opportunity to test the elective 

 blood-alkali-agar medium of Dieudonne (2) with fresh cholera material. 

 Cholera vibrios grow luxuriantly upon this medium, but other cholera- 

 like vibrios also grow ire!/. However Bacillus typhosus does not develop 

 on it and colon bacilli scarcely grow at all. Some other intestinal 

 bacteria also flourish, but not luxuriantly, and less care is necessary in 

 manipulation because many air-borne organisms either do not grow at 

 all or develop so slowly as to be a negligible quantity. Tested side by 

 side with ordinary agar plates, the relative number of cholera colonies 

 is enormously increased, they develop Faster, and, in favorable cases 

 upon direct inoculation without preliminary enrichment in peptone, the 

 diagnosis may be made therefrom in ten hours. 3 



Some of the noncholera vibrios which we examined did not differ 

 more markedly from cholera vibrios in morphology, motility, cultural 

 characteristics, production of cholera-red and pathogenicity, than may two 

 individual cholera strains. They develop in peptone with the same 

 rapidity and the colonics present the same appearance upon agar plates 

 as do those id' cholera vibrios. 



Zlatogofoff, (12i in an interesting article, lias called attention to the various 

 characteristics of the cholera vibrio which have been relied upon for diagnosis 

 and found wanting in the past, namely, growth upon gelatine, cholera-red pro- 

 duction, absence of phosphorescence, absence of hemolytic power, failure to 

 produce a soluble toxin, and others. Tie admits the specificity of Pfeiflfer's 

 reaction, but is inclined to think that agglutinability is a quality which might 

 be acquired and lost, with surprising facility. He concluded that the life of 

 cholera vibrios in water reduced their agglutinability, but that this quality could 

 be restored by certain procedures. 



Zlatogoroff worked with a total of 23 vibrios and a cholera serum with an 

 agglutinating limit of 1-20,000. He found that 5 of these strains would 

 agglutinate in a dilution of 1-5,000 and he at once considered them to be cholera 

 vibrios. After one month lie noticed that 3 of the others showed agglutination 

 in a dilution of 1-500. These had been transplanted once a week and kept twenty- 

 foUr hours in incubators at 37°C. and then at Hi to 1S°C. 



3 Doctor Bowman of the biological laboratory. Bureau of Science, has used this 

 medium in the routine examination of 200 specimens sent by the Bureau of Health. 

 The specimens were received as faeces, agar streak cultures, peptone cultures, por- 

 tion of the intestine, etc. Streak cultures were made directly on the Dieudonne" 

 medium. When cholera was present the organism grew luxuriantly, overgrowing 

 all others. A loop of the culture on the plates was transferred to a drop of aggluti- 

 nating strum on a slide, and the diagnosis quickly made, while in using ordinary 

 alkaline agar plates it was necessary sometimes to examine several colonies 

 before a positive reaction was obtained. The use of this medium certainly 

 simplifies the technique in the rapid bacteriologic diagnosis of cholera and at 

 present it is being employed in the routine examination of all specimens sent to 

 this laboratorv. 



