EPIDEMIC INFLUENZA 497 



fatality was conspicuous in those past forty-five years of 

 age and haemorrhages were absent ; in June and July, 

 1918, the disease was mild and soon recovered from, but 

 at the end of 1918 and in the spring of 1919 the disease 

 assumed a severe type, the fatality falling upon young 

 adults, and haemorrhages were frequent. These differences 

 raise a suspicion that so-called epidemic influenza is 

 more than one disease, but, on the other hand, they 

 may be due to differences of virulence or of race (cf. 

 the streptococci) of the B. influenzce and to varia- 

 tions in the occurrence and nature of the secondary 

 infecting agents. 



Apart from epidemic influenza, the B. influenzce occurs 

 in sinusitis, nasal and post-pharyngeal catarrh, bronchial 

 catarrh and bronchitis, tracheitis and broncho-pneu- 

 monia, whether these be primary or complicating measles 

 and whooping cough. It is also stated to be a rare cause 

 of meningitis. 



Various strains of the B. influenzce seem to exist, for 

 the serum of an animal inoculated with one strain while 

 agglutinating this strain actively may be without action 

 on many other strains. An individual may harbour 

 several strains. 



A vaccine prepared with killed culture is frequently 

 useful in the treatment and prevention of catarrh of the 

 respiratory tract, either alone or in combination with M . 

 catarrhalis, B. coryzce, streptococcus, pneumococcus, etc., 

 according to the organisms found to be present in the 

 secretion or expectoration. 



Attempts have been made to immunise against influenza 

 and its complications by the use of a mixed vaccine 

 containing B. influenzce, streptococci and pneumococci. 

 The results obtained are statistically not encouraging 

 as regards protective power against attack, though the 

 fatality among those vaccinated seems to be reduced. 



M.B. 32 



