THE PARATYPHOID B. BACILLUS 



437 



The following table taken from Bainbridge and O'Brien's paper will make 

 the above statements clear. 



6. Complement fixation. 



By means of the complement fixation reaction H. R. Dean has shown that 

 the paratyphoid B bacillus can be clearly differentiated from the typhoid 

 and paratyphoid A bacilli and also from the aertrycke bacillus (p. 428 for 

 technique). 



Unless a suitable dilution of antiserum be employed the group antibodies 

 in the serum will mask the specificity of the reaction. Dean has however 

 shown that these group antibodies can be removed by absorption previously 

 to carrying out the complement-fixation reaction. Thus, when a para- 

 typhoid B antiserum is absorbed with an emulsion of paratyphoid A bacilli, 

 the serum loses its capacity for binding complement in the presence of either 

 a paratyphoid A extract or a typhoid extract. After absorption with a para- 

 typhoid B emulsion the group antibodies are found to be removed, together 

 with the antibodies specific for paratyphoid B. 



SECTION IV. ISOLATION AND IDENTIFICATION OF THE 

 PARATYPHOID B. BACILLUS. 



In cases of paratyphoid fever the organism may be isolated from the 

 blood-stream, or from the stools or urine, and after death from the spleen. 



In localized paratyphoid infections e.g. cholecystitis, gall stones, abscesses 

 in various parts of the body material (bile, pus, etc.), from the site of infec- 

 tion must be used. 



The material should be sown in dulcite (1-2 per cent.) broth or dulcite 

 peptone water incubated at 37 C. for 24 hours or longer in some cases the 



1 Bacillus F was an organism isolated by Williams. Rundle and Murray from cases 

 of summer diarrhoea and shown by this test to be identical with B. aertrycke. 



