214 THE ROYAL SOCIETY OF CANADA 



Sample A.L. 3 produced gas in 3 days. 



3 « « 4 « 



4 did not produce in 5 days. 



These four were re-inoculated into fresh litmus milk and gave gas and 

 acid in 16 hours. 



Sample J.D. 4 produced gas after 3 days. 



6 did not produce gas in 6 days. 

 These six transferred to fresh litmus milk gave gas and acid in 16 hours. 



Hence our conclusions are that of the 135 black colonies tested, 

 all gave strong gas and acidity without coagulation in litmus milk, 

 which is taken as presumptive evidence that the organism belongs 

 to the colon-aerogenes group. 



Further, we conclude that these small colonies represent colon- 

 aerogenes organisms in a weakened condition, which regain their 

 activity when grown for some days in sterile milk. Although no ex- 

 ceptions were found we consider this result valuable as it shows the 

 reliability of the aesculin test in this detailed analysis. 



References. 

 Harrison, F. C, Savage, A. and Sadler, W. The Milk Supply of Montreal. Mac- 



donald College Bulletin. September, 1914. 

 Klotz, Oscar, and Rankin, A. C. The reaction of various bacteria upon Aesculin 



agar. The Journal of Infectious Diseases. Vol. VII. Jan. 15th, 1910. 



pp. 67-72. 

 Harrison, F. C, and Vanderleck, J. Aesculin Bilesalt media for the isolation of B. 



coli and B. typhosus. Proceedings and Transactions of the Royal Society 



of Canada, 1909. Vol. Ill, section IV. 

 Harrison, F. C, and Vanderleck, J. Aesculin Bilesalt media for water analysis. 



Centralblatt fur Bakteriologie. II Abt. 22 pp. 547-551. 1909. 



Note 1. 

 Trans. Royal Society of Canada. 



Section IV, 1909, page 147. 



Aesculin Bilesalt Media for the Isolation of B. Coli and B. typhosus. 

 Preparation of Aesculin-Bilesalt Agar. 



The directions for making a litre of aesculin-bilesalt agar are as follow: — 



Boil until dissolved 15 grams of agar, 2-5 grams commercial bilesalt and 

 10 grams peptone (Witte) in 1,000 c.c. of distilled water. Neutralise with a 

 normal solution of sodium hydrate. Cool below 60°C., add the whites of two 

 eggs or a sufficient quantity of a solution of albumen, bring to the boil and 

 filter as soon as the albumen has coagulated properly. Try the acidity and 

 neutralise if necessary, and then add to the clear hot filtrate 1 gram aesculin 

 (Merck) and 1 gram iron citrate scales (Merck) After these substances are dis- 

 solved test the acidity with decinormal soda solution. It will be found to be 

 about -fO-6 as a solution of 1 gram iron citrate scales in 1,000 c.c. water gives an 

 acidity of + 0-56. In case the acidity is too high add alkali until the reaction 

 is -f-O-ô and if the acidity is too low add more iron citrate until their reaction 

 is -I-0-6. 



