xii] PATHOGENIC BACILLI : GROUP C 257 



announcement that in all cases of influenza there are 

 present in the characteristic grey purulent bronchial secretion 

 enormous numbers of minute non-motile bacilli. He de- 

 scribes these as occurring only during the acute stages and 

 gradually diminishing in numbers as the disease abates. 

 The bacilli, he tells us, are very minute, about the thickness 

 of the well-known bacilli of Koch's mouse septicaemia, but 

 only half their length ; they stain with some difficulty in 

 anilin dyes, requiring a somewhat prolonged application of 

 the dye. In stained specimens these bacilli have a charac- 

 teristic appearance, inasmuch as their protoplasm is segre- 

 gated into a stained granule at each end while the middle 

 portion remains unstained and shows only the outline of the 

 sheath. Thus the bacillus looks like a diplococcus, and 

 where two such bacilli are placed end to end they look like 

 a chain (streptococcus) of four spherical cocci. In the 

 sputum these bacilli occur in smaller and larger masses, 

 occasionally almost as a pure culture. In severe cases they 

 form continuous masses in the peribronchial tissue and also 

 in the subpleural lymphatics, and they are also met with 

 inside the leucocytes of the sputum. As the disease passes 

 off, so the bacilli disappear from the sputa. These bacilli 

 are constantly present in influenza, but do not occur in the 

 bronchial secretion of other bronchial or pulmonary affec- 

 tions. 



Kitasato, in the same paper, gives his observations on the 

 cultivation of these bacilli of Pfeifler, and records that they 

 have cultural characters by which they can be readily dis- 

 tinguished from other bacilli : that they are, in fact, a 

 definite species not occurring in any disease except in 

 influenza. They do not thrive at temperatures below 28° C., 

 that is to say at temperatures at which nutrient gelatine 

 still keeps its solid condition. They grow well in broth and 



