EL TOR VIBRIOS 441 



Ivanoff and Berolinensis reacted completely with cholera 

 serum. Conversely, positive reactions with cholera vibrios 

 were obtained with Massoivah, Danubicus, and Elwers sera, 

 while Massowah and Elwers react completely to each other. 

 From these considerations it would therefore seem probable 

 that some of these vibrios Sanarelli, Berolinensis, and 

 Ivanoff may be varieties of the Koch vibrio. The Massowah 

 vibrio is usually considered not to be a true cholera vibrio. 



Ruffer 1 in 1905 at El Tor isolated vibrios, which may 

 be distinguished as "El Tor vibrios," from the intestine 

 of pilgrims returning from Mecca and suffering from various 

 diseases (dysentery, diarrhoea, pneumonia, rheumatism), 

 but among whom there had been no cholera, and who had 

 not been in contact with cholera. These vibrios were sub- 

 j ected to detailed examination by the agglutination, satura- 

 tion and fixation tests, and Pfeiffer's reaction with Berlin 

 cholera-immune serum, and also by the haemolysis test. 

 Vibrios isolated from a previous epidemic of cholera (re- 

 ferred to as Group 1), and other vibrios isolated from cholera 

 and other stool (Groups 3 and 4), were also compared 

 with the El Tor vibrios. RufTer's results were as follows : 



Group 1 (undoubted cholera vibrios). Those which 

 react positively to the four principal tests with cholera 

 serum namely, the agglutination, saturation, and fixation 

 tests, and Pfeiffer's reaction. They do not haemolyse, 

 even when remaining in contact with red corpuscles for 

 three days at the temperature of the laboratory. 



Group 2. The second group contains the vibrios agglu- 

 tinated by, and giving the saturation and PfeifTer's reactions 

 with, cholera serum, but not fixing the cholera-immune 

 body. These vibrios are strongly hsemolytic. This group 

 consists of the El Tor vibrios only. 



1 Researches on the Bacteriological Diagnosis of Cholera. Sanitary, 

 Maritime, and Quarantine Council of Egypt, Alexandria, 1907. (Also 

 Brit. Med. Journ., 1907, vol. i, p. 735.) 



