578 Asiatic Cholera 



(i) The typical morphology. The true cholera organism is short, 

 has a single curve, is rounded at the ends, and possesses a single 

 flagellum. (2) The infectivity. Freshly isolated cultures should be 

 pathogenic for guinea-pigs and harmless to pigeons. (3) Vegeta- 

 tive: The organism should liquefy 10 per cent, gelatin and should 

 not coagulate milk. (4) Metabolic: the indol reaction should be 

 marked. (5) Immunity reactions: the organism when injected 

 into guinea-pigs in ascending doses should occasion immunity against 

 the typical cholera organism, and the serum of the immunized 

 guinea-pig, when introduced into a new guinea-pig, should protect 

 it from infection and produce Pfeiffer's phenomenon. The blood- 

 serum of animals immunized against the cholera organism should 

 agglutinate the doubtful organism in approximately the same 

 dilution, and that of animals immunized to the doubtful organism 

 should agglutinate the cholera organism reciprocally. Both organ- 

 isms should have equal capacity for absorbing complements and 

 amboceptors from blood-serum. (6) The true cholera organism 

 should not be hemolytic. Too much reliance must not be placed 

 upon the agglutination tests alone, as will be made clear by a perusal 

 of the paper upon Bacteriological Diagnosis of Cholera by Ruffer.* 



Pfeiffer and Vogedesf have applied the "immunity reaction" 

 to the identification of cholera spirilla in cultures. A hanging 

 drop of a I : 50 mixture of a powerful anticholera serum and a particle 

 of cholera culture is made and examined under the microscope. 

 The cholera spirilla at once become inactive, and are in a short time 

 converted into little rolled- up masses. If the culture added be a 

 spirillum other than the true cholera spirillum, instead of being 

 destroyed the micro-organisms multiply and thrive in the mixture 

 of serum and bouillon. 



Immunity. — One attack of cholera usually leaves the victim 

 immune from further attacks of the disease. Gruber and Wiener,J 

 Haffkine,§ Pawlowsky,|| and Pfeiffer** have immunized animals 

 against toxic substances from cholera cultures and against living 

 cultures. 



Sobernheimft found the Pfeiffer reaction specific against cholera 

 alone, and thought the protection not due to the strongly bactericidal 

 property of the serum, but to its stimulating effect upon the body- 

 cells; for if the serum be heated to 6o°-7o°C., and its bactericidal 

 power thus destroyed, it is still capable of producing immunity. 

 This, of course, is in keeping with our present knowledge of the 

 immune body, which is not destroyed by such temperatures. 



* "British Medical Journal," March 30, 1907, i, p. 735. 



f'Centralbl. f. Bakt. u. Parasitenk.," March 21, 1896, Bd. XK, No. 11. 



i "Centralbl. f. Bakt.," 1892, xiv, p. 76. 



§ "Le Bull. m6d.," 1892, p. 1113, and "Brit. Med. Jour.," 1893, p.' 278. 



1] "Deutsche med. Wochenschrift," 1893, No. 22. 

 ** "Zeitschrift fur Hygiene," Bd. xvni and xx. 

 tt "Zeitschrift fur Hygiene, xx, p. 438. 



