502 



THE CHOLERA VIBRIO 



3. To the contents of each flask add 150 c.c. of the water under examina- 

 tion (that is, up to the mark on the flask) and incubate at 37 C. If the 

 water should contain vibrios a thin pellicle will form on the surface of the 

 liquid in about &-10 hours. A trace of this film may be examined micro- 

 scopically and one or two sub-cultures in series can be made in the gelatin- 

 peptone-salt medium [or in peptone-water] ; and if need be the organism can 

 be isolated on agar in the manner described above. 



2. Identification. 



Having isolated a vibrio from the excreta or from water it is then necessary 

 to identify the organism, because there are a number of vibrios which must 

 be regarded as harmless saprophytes. Numerous species of vibrios have 

 been found in different waters by Metchnikoff, Blachstein, Sanarelli, the 

 last-named observer has described no less than 32 species in the Paris water. 



There is at present no known characteristic which is pathognomonic of the 

 cholera vibrio, and when vibrios are found in water in the absence of any 

 epidemic of cholera it may be impossible to identify them. The following 

 are generally regarded as the classical characteristics of the cholera vibrio : 



1. The appearances presented in gelatin stab and plate cultures, p. 493. 



2. The presence and the number of flagella, p. 492. 



3. The nitroso-indol reaction in peptone-water cultures, p. 494. 



4. The virulence for guinea-pigs (choleraic peritonitis), p. 489. 



5. The immunity reaction, p. 499. 



6. Agglutination by an anticholera serum and the occurrence of Pfeifler's 



phenomenon, p. 500. 



Attention has already been drawn in the course of this chapter to the lack 

 of specificity and constancy of these characters ; the most reliable is the 

 agglutination reaction with the specific serum. A better 

 means of identifying the cholera vibrio will perhaps consist 

 in feeding young rabbits on the suspected vibrio either alone 

 or mixed with ancillary micro-organisms. It seems probable 

 that the application of the "fixation of the complement" 

 reaction may be of considerable use in the identification of 

 vibrios. 



The Vibrio of Finkler-Prior. 



This vibrio was discovered by Finkler and Prior in the stools 

 of a man suffering from acute enteritis. It was found again by 

 the same observers in the stools of persons infected with cholera 

 nostras, and it is possible that this was the organism found by 

 Ruete and Enoch in the stools of a woman suffering from a fatal 

 attack of diarrhoea. 



The vibrio which Rommelaer took to be the Finkler- Prior vibrio 

 really belongs to the group of the true cholera vibrios. 



Experimental inoculation. When inoculated intra-peritoneally 

 into a guinea-pig the Finkler-Prior vibrio sets up a fatal peri- 

 tonitis. 



A fatal infection can be produced in pigeons by inoculating 

 the organism into the pectoral muscle. In man the consumption 

 of an agar culture of the vibrio after the contents of the stomach 

 have been made alkaline produces slight intestinal disturbance 

 FIG 242 Vibrio ( Metch nikoff). 

 of Finkler-Prior. Microscopical appearance. Microscopically the Tinkler-Prior 

 Stab culture in gela- vibrio is similar to the cholera vibrio but the former is slightly 

 swollen in the centre and tapered a,t the ends. The two organ- 

 isms give the same staining reactions and both are gram-negative. 

 The Finkler-Prior vibrio is motile and has a single flagellum. 



