CHOLERA AND CHOLERA-LIKE VIBRIOS. 407 



He passed his organisms through animals (guinea pigs), once in three or 

 four weeks, and after 54 generations raised the agglutinability so that it was 

 exhibited in a dilution of 1-10,000. He was able to accomplish this only after 

 he combined animal passage at rather infrequent intervals, with frequent trans- 

 planting upon good media. Neither of these methods alone sufficed to develop 

 agglutinative properties. For example: Culture 15; dose ~ slant; November 

 6, no agglutination ; November 6, A slant, guinea pig, died on November 9. 

 Culture peritoneal on agar; November 10, agglutination 1-200; November 24, 

 same repeated, agglutination 1-400; the same culture passed through 4 pigs 

 without intermediate culture only developed an agglutinative power of 1-100. 



He continued this treatment for three months, at the end of which time 

 the vibrio had agglutinated in a dilution of 1-5,000. The culture transplanted 

 without animal passage for three months agglutinated in 1-200. 



To summarize his work, there were in all twenty-three vibrios studied : 

 5 agglutinated at the beginning in a dilution of 1-5,000; the agglutinating titre of 

 the serum was 1-20,000; 18 vibrios did not agglutinate; 10 acquired agglutinative 

 properties after six months, in a dilution of 1-5,000: 7 remained negative: and 

 1 died out. 



Zlatogoroff concluded that during cholera epidemics, in addition to typical 

 forms, atypical cholera vibrios which have lost certain biologic qualities may also 

 be present in water. In time, under certain artificial conditions, these vibrios 

 regain all the qualities of the typical cholera vibrios. He states: "Failure to 

 agglutinate these water vibrios does not prove that they are not cholera, 

 as cholera vibrios can change into saphropytic subvarieties very easily and 

 can also lose their ability to agglutinate with cholera serum." 



Barrenscheen ( 1 ) repeated that part of the work of Zlatogoroff which 

 related to the reduction of agglutinability by keeping the vibrio for varying 

 periods in water. He found that a cholera vibrio which agglutinated in a 

 dilution of 1-40,000 at the beginning, did not agglutinate above 1-5,000 after 

 eight days in distilled water. Cultures upon agar from the bacterial residue 

 after centrifugation was also tested. The agglutinability had dropped to 1-400. 

 Restoration or increase of agglutinability was not achieved after three weeks, 

 although Barrenecheen succeeded in increasing the luxuriance of growth. He 

 concludes that there is a passing out of the agglutinable substance into the water. 



To test whether noncholera vibrios may acquire agglutinability to 

 c-holera serum, 12 of our own strains which seemed most favorable were 

 selected. They all possessed a morphology, motility, and cholera-red 

 production similar to those of cholera vibrios. They were treated in a 

 manner similar to that suggested by Zlatogoroff. They were passed 

 through guinea pigs between Xovember 1 and 8, December and Jan- 

 uary, and transplanted upon agar every five or six days. After each 

 animal passage, agglutination tests were made with a good cholera serum. 

 At the end of two months, with 3 animal passages and 12 intermediate 

 transplantations,. not the slightest change was noticeable in the behavior 

 of the organism to cholera agglutinating serum. 



Our vibrios isolated from the human intestines, from water or other 

 sources which are negative to agglutination tests with cholera serum and 



