206 N. S, FERRY AND ARLYLE NOBLE 



First absorption, serum 1-10 incubated two hours. 

 Second absorption, serum 1-20 incubated two hours. 

 Third absorption, serum 1-40 incubated eighteen hours. 



SUMMARY AND DISCUSSION 



1. After repeated transplantings Bad. pertussis has been found 

 to give the same cultural reactions as B. bronchisepticus — the 

 tan growth on potato and the alkaline reaction in litmus mik being 

 the most prominent characteristics. The difference in motihty 

 and the tardiness in the reactions of Bact. pertussis on culture 

 media are differential characteristics. 



2. B. bronchisepticus antiserum agglutinates not only B. 

 bronchisepticus (1-6400 to 1-2,000), but also Bact. pertussis 

 (1-400 to 1-6400). 



3. Bact. pertussis antiserum on the other hand agglutinates 

 only the pertussis bacillus. 



4. There was no cross agglutination between B. bronchisepticus 

 and a pertussis-like bacillus or three hemoglobinophilic bacilli. 

 Also, there was no agglutination between Bact. pertussis and these 

 organisms. 



5. Bact. pertussis antiserum of high agglutination titre (1-3200 

 to 1-20000) has been produced, in rabbits, by three intravenous 

 inoculations (three days apart) of sterile, unheated vaccines of 

 fifteen strains of Bact. pertussis. 



Povitzky and Worth, in the article cited above, conclude that, 



A strongly agglutinating pertussis serum was best obtained in the 

 rabbit by ten to twelve intraperitoneal inoculations of living culture s at 

 seven-day intervals. Agglutinins are also produced by vaccines, but 

 not as abundantly as by living cultures. 



After ten to twelve inoculations of live cultures, their rabbits 

 show a titre of from 2400 to 5000 and one rabbit went to 10000. 



Over 50 per cent (9 out of 17) of our rabbits show a titre of 

 20000, and only two were as low as 3200. The one rabbit in 

 the tables of Povitsky and Worth treated with killed vaccine 

 (heated) shows a titre of 1600 after the sixth inoculation and no 

 agglutination after the fourth. They also say. 



