176 APPLIED BACTERIOLOGY FOR NURSES 



by some virus, perhaps ultramicroscopic (filterable), as 

 yet unidentified, and that the so-called influenza bacil- 

 lus (Pfeiffer's bacillus) is really a secondary invader. It 

 would seem probable that the original infection makes 

 secondary invasion by other germs, especially influenza 

 bacilli, pneumococci, and streptococci, much more easy. 

 In this connection it may be stated that a French inves- 

 tigator, Nicolle, claims to have demonstrated the filterable 

 nature of the influenza virus. 



Fig. 56.— Pfeiffer's bacillus; X 1000 (Kr^l). 



Now and then the influenza bacillus produces a tj^ical 

 meningitis. This is very fatal. A bacillus similar to the 

 influenza bacillus appears to be associated with whooping- 

 cough. Prophylaxis in influenza is similar to that dis- 

 cussed under Pneumococcus. 



Micrococcus of Malta Fever. — A very small, rounded 

 or slightly oval micro-organism. Gram-negative, and 

 growing rather feebly on artificial media. The organ- 

 ism appears to be present in the feces of goats in Malta, 

 and probably contaminates the milk. In man a typhoid- 



