WHOOPING-COUGH 499 



green be added in the proportion of 1 in 500,000, streptococci and 

 pneumococci are inhibited, but the B. influenzce grows freely. 



Whooping-cough (Pertussis) 1 



An influenza-like bacillus has been isolated by Koplik, Czaplew- 

 ski and Hensel, Davis and others in this disease, but the researches 

 of Bordet and Gengou have shown that it is distinct from the 

 influenza bacillus. 



The B. [Hemophilus] pertussis is a minute bacillus, very like the 

 B. influenzce, non-motile, non-sporing, and Gram -negative. It is 

 scanty in the bulk of the expectoration, but is abundant in the 

 viscid exudate, rich in leucocytes, coming from the depth of the 

 bronchi, and voided at the end of a paroxysm of coughing. 



It is best isolated on a medium consisting of defibrinated blood 

 (human or rabbit), thoroughly mixed with an equal volume of 



3 per cent, agar containing a little extract of potato made with 



4 per cent, aqueous glycerin. It forms on this a fairly thick 

 whitish streak, the subjacent blood being hsemolysed. It may 

 also be grown in serum or blood broth in shallow layers. After 

 acclimatisation to artificial media it will develop on the ordinary 

 laboratory media. 



The B. pertussis is agglutinated feebly by the blood of patients, 

 but complement-fixation is marked. 



Monkeys are stated to develop a typical whooping-cough on 

 inoculation, but the ordinary laboratory animals are susceptible 

 only to massive intraperitoneal or intravenous inoculation, death 

 ensuing from a septicsemic process. 



Freeman has treated the disease with a vaccine. Doses of 

 5-20 millions were used, and about 68 per cent, of the cases 

 improved. 



1 See Bordet, Brit. Med. Journ., 1909, vol. ii, p. 1062. 



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