59 



mia and some haemorrhagic inflammation of the various organs, 

 notably the lungs (Gosio & Missiroli and others). 



All these facts in connection with the occurrence of Pfeif- 

 fer's bacilli in the fine bronchioles and to some extent in the 

 lung tissue itself as well as the formation of specific antibodies 

 in the patients, indicate that the symptom's and pathological 

 changes of influenza to a large extent can be produced by 

 Pfeiffer's bacilli, but they are inadequate to prove its primary 

 significance in this disease. 



Several authors insist that the bacillus is the true in- 

 fluenza microbe, that is to say the primary virus of influenza, 

 which lies at the root of the whole pandemic. 



Pfeiffer and his collaborators in defence of this attitude 

 affirm in particular that the bacillus is closely associated with 

 influenza and is only exceptionally met with apart from 1 in- 

 fluenza epidemics. But when Leiciitentritt (2) after having 

 mentioned that Selter and Neufeld had not found Pfeif- 

 fer's bacillus in a number of years, says: „Gegen solche ausfiihr- 

 lichen Forschungen verschwinden die vereinzelten Influenza- 

 bazillenbefunde bei akuten Infektionskrankheiten, wie sie von 

 einzelnen Autoren, Jochmann, Wohlwill, Klienererger u. a. 

 m. beschrieben wurden . . . .", this m'ust be looked upon as 

 a rather one-sided view. 



If one reviews, without any preconceived notions regarding 

 the significance of Pfeiffer's bacillus, the whole of our knowledge 

 relating to its occurrence, the. following conception, in the 

 author's opinion, best accords with the observed facts. 



Pfeiffer's bacillus is a microbe which is mainly adapted 

 to living in -the mucous membranes of the respiratory tract 

 of man. It is able to exist for a time in healthy persons after 

 being transferred to them from 1 other sources, but in the long 

 run it can only maintain its foothold in the healthy mucous 

 membrane with difficulty. It finds its ideal conditions for 

 development in mucous membranes which are already in a 

 catarrhal state such as is produced by another bacterial in- 

 fection, but the nature of the infection is a matter of indiffe- 

 rence. It may be influenza taken in its widest sense, whooping- 

 cough, measles, or tuberculosis. A catarrhal condition which 

 affects large tracts of the mucous membrane of the respira- 

 tory passages is common to these infections, especially the 



