166 BIOLOGY AND TECHNIQUE 







SPECIAL MEDIA FOR THE ISOLATION OF CHOLERA SPIRILLA 



Dieudonnc Medium.** To 70 parts of ordinary 3 per cent agar made 

 neutral to litmus, add 30 parts of a sterile mixture of defibrinated beef 

 blood and normal sodium hydrate. 



This is sterilized by steam before being added to the agar. This alkali 

 agar is poured into plates and allowed to dry several days at 37, or 5 minute* 

 at 60. The material to be examined is smeared on the surface of these 

 plates with a glass rod. 



Aronson's Medium for Cholera Stool Isolation. 42 This medium is pre- 

 pared as follows: 35 grams of agar are added to 1 liter of tap water and 

 soaked over night. 



Add 10 grams of meat extract, 10 grams of pepton, 5 grams of sodium 

 chloride and heat in steam sterilizer from 4 to 5 hours. The particles are 

 allowed to settle by letting the hot agar stand, and the clear supernatant 

 agar poured into flasks to hold 100 c.c. each. 



The following solutions are previously made and sterilized for l /2 hour in 

 the Arnold: 



1. 10 per cent solution of sodium carbonate 



2. 20 per cent solution of cane-sugar 



3. 20 per cent solution of dextrin 



4. saturated solution of basic fuchsin 



5. 10 per cent solution of sodium sulfite (sterilized by being brought to 



a boil) 



To 100 c.c. of agar add 6 c.c. of the 10 per cent solution of sodium 

 carbonate and heat for 15 minutes at 100 C. The agar, because of the 

 alkalinity, becomes brown and cloudy. While hot, add 5 c.c. of the 20 per 

 cent solution of cane-sugar, 5 c.c. of the 20 per cent solution of dextrin, 

 0.4 c.c. of the saturated solution of basic fuchsin, and 2 c.c. of the 10 per 

 cent sodium sulfite solution. The flask is allowed to stand to let the coarser 

 particles settles, and plates are poured with the clear supernatant fluid. The 

 principle of this medium, like Dieudonne's, depends upon the ability of 

 cholera spirilla to grow on very alkalin media and upon their ability to 

 split polysaccharites with acid and aldehyde formation. 



Cholera strains, recently from the human body, give large red colonies 

 in from 15 to 20 hours, whereas, the colon colonies are smaller and colorless. 

 Teague and Travis 43 found that strains of cholera spirillum that had been 

 out of the human body for some time did not yield red colonies promptly, 

 but they obtained excellent results even with these cultures, if they added 

 0.25 per cent nutrose to Aronson's medium. 



"Dieudonne, Cent. f. Bakt., 1., orig., 1909. 



"Aronson, Deut. med. Woch., 41, 1915, 1027. 



43 Teague and Travis, Jour, of Infec. Dis., 18, 1916, 601. 



