404 BACTERIA PATHOGENIC TO MAN 



B. Suspected water. 



Add to 500 c.c. or 1 litre of the water to be examined in a flask half- 

 full enough peptone-salt solution (20 per cent, peptone and 10 per cent. 

 NaCl) to make a 1 per cent, solution of peptone. Then proceed as 

 in A. 



SPECIFIC SERUM REACTIONS. All authors now agree that the differ- 

 entiation of the cholera vibrio from other similar vibrios cannot always 

 be made by the cultural method, nor is the usual inoculation of animals 

 sufficient. For this purpose serum is employed either by making intra- 

 peritoneal injections of a surely fatal dose of the suspected spirillum 

 along with the serum of animals immunized to undoubted cholera 

 cultures, or to note whether specific protection is afforded, or the 

 Gruber-Widal test is carried out in such a way as to determine if spe- 

 cific agglutination of the spirilla occurs. 



Spirilla More or Less Allied to the Cholera Spirillum. 



The examinations of the stools of persons suffering from cholera 

 have revealed, in a small percentage of cases, spirilla resembling either 

 very closely or having a fair degree of similarity to the true cholera 

 organisms. Further, in a small percentage of cases having choleraic 

 symptoms no true cholera vibrios have been found, but instead other 

 spirilla resembling them more or less closely. 



These may differ in having two or more end flagella, in size, in pro- 

 duction of nitrites, etc., or they may be identical in the tests commonly 

 employed. They all differ in the specific agglutination and bacterio- 

 lytic tests from the cholera spirilla and among themselves. 



In a recent epidemic in Egypt, Gottschlich obtained from sixteen cases 

 spirilla differing from the true spirilla, and found every one distinct 

 in some characteristic from all others. Some were pathogenic for 

 pigeons, through inoculation of a small quantity into the breast muscle ; 

 others were atypical in their development in nutrient gelatin. None 

 of these micro-organisms injected into animals induced production of 

 agglutinins for the true cholera spirilla. 



Kolle and Gottschlich consider these various spirilla found by them 

 in Egypt as well as others found by different investigators in India, 

 Germany, and elsewhere to be saprophytes. It is more probable, in 

 the writer's opinion, that some of them must be considered as bearing 

 a part in exciting a cholera-like disease, but that they are not very 

 pathogenic and require very favorable conditions before they can exert 

 their action. 



Some special varieties of spirilla resembling those of cholera have 

 received especial attention on account of having been obtained before 

 it was known that so many cholera-like vibrios existed. The vibrio 

 Berolinensis, cultivated by Neisser from Berlin sewage-water; the 

 vibrio Danubicus, cultivated by Hausser from canal-water, and the 

 vibrio of Massowah, cultivated by Pasquale from a case during an 

 epidemic of cholera, all are negative to the specific serum reactions, 



