XII, B, 2 Crowell and Johnston: Cholera Cases 89 



a serum that agglutinates the true cholera vibrio. They are 

 strongly hsemolytic and liquefy gelatin faster than do the true 

 cholera vibrios. Such nonagglutinable choleralike vibrios have 

 been found in cases that have no relation to cholera and in true 

 cholera cases either in association with the true cholera vibrio 

 or after the true cholera vibrio has disappeared. Evidence va- 

 ries as to whether it is possible for the true cholera vibrio to 

 lose its agglutinability ; it seems probable that the agglutino- 

 genic capacity of the true cholera vibrio is more constant than 

 its agglutinability. 

 0'Connell(33) states: 



These choleroid organisms are an extremely interesting phenomenon. 

 Their relationship to true cholera may be said to have been established 

 but not defined. Bacteriologists in service in the Far East have noted their 

 appearance in specimens subjected to microscopical examination immediately 

 before and during cholera epidemics. They are not known v/here cholera 

 is not or has not been recently. Their morphology and biological charac- 

 teristics are such that it is impossible to distinguish them from true cholera 

 organisms by microscopic examination. Agglutination is the only test under 

 which their reaction is differentiated from that of the cholera vibrio. 



Certain authors, Zlatogoroff(45) and Horowitz, (24) have made 

 the assertion that under certain conditions of growth and en- 

 vironment the cholera organism loses all or some of its typical 

 biological characters, regaining them under certain favorable cir- 

 cumstances. Clinicians in the Philippines have repeatedly made 

 the statement that cholera was endemic, notably Heiser(2l) and 

 Clements, (4) although the diagnosis was unconfirmed bacterio- 

 logically. Any purely theoretical conjecture such as this, un- 

 supported by exact laboratory evidence, must be set aside, and 

 the final decision must be based on experimental facts with abso- 

 lute exclusion of possible error. The causal relation between 

 the seasonal outbreaks of cholera in India and the vitality of 

 the cholera vibrio outside the human body has already been 

 demonstrated by Greig. 



Few of the known microorganisms in the etiology of human 

 diseases appear to be so variable in their morphology as the 

 cholera vibrio. Ohno("4) has called attention to the striking 

 changes noted in shape and motility in cholera strains, and Ho- 

 vorka(25) has mentioned the impairment of agglutinability. 

 Such changes as these do not seem to be permanent, and some 

 of the causative factors are known, so that it is possible practi- 

 cally to cause such changes to appear at will. 



It has been well established that the reported inagglutinability 

 of certain cholera strains was due to the use of an immune 



