480 INFECTION AND IMMUNITY. 



The length of the negative phase varies with the 

 severity of the symptoms. The fulminating cases 

 have a short negative phase ending in death. The 

 antibodies reach their height during convalescence, 

 the bacteriolysins usually developing most rapidly. 

 In most cases the three antibody curves run 

 parallel, but the bacteriolysins may be much more 

 highly developed than the opsonins. 



According to Pfeiffer and Marx, the antibodies 

 are produced in the blood-forming organs. An 

 attack of cholera confers immunity of prolonged 

 duration, although it is not always absolute. 



Passive immunity is readily induced in animals 

 by injection of anticholera serum. As in other 

 instances, it is of short duration. Doubtless the 

 same condition may be induced in man. Besredka 

 has proposed mixed immunization for protective 

 inoculation, using killed bacteria which have been 

 saturated with the specific amboceptors. 



serotherapy Serotherapy has been no more successful in 

 nation, cholera than in typhoid fever. The antitoxic 

 serum of Eoux and others has had no practical 

 trial. According to Achard and Bensaude, the 

 serum of cholera patients, on the third or fourth 

 day of the disease, agglutinates the cholera vibrio. 

 However, they used the serum in dilutions of 1-20. 

 and in this strength even normal human serum 

 may be agglutinating (Pfeiffer and Kolle, cited by 

 Paltauf). Convalescents even after seven months 

 may show an agglutinating power of from 1/100 to 

 1/120. 



The bacteriologic examination of the stools is 

 the most reliable means of early diagnosis (see 

 above). 



