CHAPTER XXXIII. 



PFEIFFER'S INFLUENZA BACILLUS. THE H^MOGLO- 

 BINOPHILIC BACILLI. THE BACILLUS OF 

 WHOOPING COUGH. 



Introduction. 



Section I. Experimental inoculation, p. 505. 



Section II. Morphology and cultural characteristics, p. 506. 



Section III. Biological properties, p. 508. 



1. Vitality and virulence, p. 508. 2. Toxin, p. 508. 3. Immunity and serum 



therapy, p. 508. 4. Agglutination, p. 509. 5. Secondary infections and ancillary 



micro-organisms, p. 509. 

 Section IV. Detection and isolation of the bacillus, p. 510. 



The hsemoglobmophilic bacilli. 



1. Pfeiffer's pseudo-influenza bacillus and similar organisms, p. 510. 2. The 

 bacillus of acute contagious conjunctivitis, p. 510. 3. The bacillus of sub-acute 

 conjunctivitis, p. 511. 



The bacillus of whooping cough, p. 511. 



THE Bacillus influenzce was discovered by Pfeiffer whose investigations 

 were subsequently confirmed by Weichselbaum, Huber and others. 1 



Influenza is a disease peculiar to man. Pfeiffer's bacillus is found in the sputum, 

 nasal mucus and respiratory passages of those suffering from the disease. 



The organism may set up foci of broncho -pneumonia in the lung and may also 

 be the cause of some of the sequelae of the disease : pleurisy, meningitis, and perio- 

 stitis (Meunier). The bacillus may still be present in the sputum some weeks after 

 all symptoms of the disease have disappeared and for an even longer time in chronic 

 lesions of the lung e.g. tuberculosis and other conditions. 



The symptoms point to influenza being an intoxication rather than a generalized 

 infection and Pfeiffer was never able to isolate the organism from the blood stream. 

 On the other hand Meunier found Pfeiffer's bacillus in the blood in four out of eight 

 cases of the disease examined by him during life and Ghedini during an epidemic of 

 influenza isolated the organism from blood taken from the bend of the elbow (64 

 out of 100 cases) and from material obtained by puncture of the spleen during the 

 febrile attack (57 out of 100 cases). Post mortem, Rosenthal found the bacillus in 

 the blood of the heart in all the fatal cases he examined. 



Pfeiffer's bacillus has not been found in by any means all cases of clinical 

 influenza, many of which are due to infection with the Micrococcus catarrhalis. 

 the Pneumococcus and possibly with other organisms. Pfeiffer failed to isolate 

 the bacillus in the 1899 epidemic, and in a very severe epidemic at Eennes 



1 The micro-organism found by Canon and Bruschettini in the blood of persons suffer- 

 ing from influenza differs essentially from Pfeiffer's bacillus in that it is a small strepto- 

 coccus which grows well on ordinary media and is pathogenic to rabbits. 



