4G 



Morphology. 



After having seen that we cannot make use of virulence 

 for grouping the haemoglobinophilic bacteria, we will now 

 consider differences of another kind in the group which as 

 before we will call Pfeiffer's bacillus. 



This question has already been touched upon in Pfeiffer's 

 (2) fundamental work. From 3 autopsies on cases of broncho- 

 pneumonia complicating diphtheria, bacilli were cultivated 

 which were considerably larger than ordinary Pfeiffer's bacilli 

 with a greater tendency to form threads (with what justifica- 

 tion Pfeiffer and many others call these threads „Schei il- 

 ia den" is not evident). But in their remaining characters, espe- 

 cially their growth only on blood agar and the appearance of 

 the colonies, they entirely resembled Pfeiffer's bacilli. He 

 termed these divergent forms „pseudo-influenza bacilli" and 

 regarded them as distinct from, but closely related to „true 

 influenza bacilli". 



Since then many investigators, in fact most of those who 

 had worked more extensively with Pfeiffer's bacillus have obser- 

 ved similar forms. Even after only a few years had passed there 

 was general agreement that the distinction between the „true 

 influenza bacillus" and the „pseudo-influenza bacillus" on this 

 purely morphological basis was untenable. Pfeiffer himself 

 also subscribed to this view. 



After going through the descriptions of the morphology of 

 Pfeiffer's bacillus by the various authors who have given detailed 

 information about it (Pfeiffer (2), Pielicke, Lindenthal, 

 Grassberger (2), Slatineano, Susswein, Albrecht & Ghon, 



CanTANI (1), FlCHTNER, KORENTSCHEWSKY, BEALL, WoLLSTEIN 



(1,3), Tedesko, Ellermann, Woiilwill, Davis (1,2), Hubsch- 

 mann, Levinthal, Mc. Intosh, Hundeshagen, Fromme, Leich- 

 tentritt, ol.sen (2), dlck & murray, spooner, scott, & 

 Heath, Legroux, Skajaa, Carpano (1), Seligmann & Wolf, 

 Preuss, Wade & Manalang and others), one gets the follow- 

 ing impression of the morphology of Pfeiffer's bacillus. 



In sputum etc. (but not in spinal fluid) it is met with 

 nearly always in the form of very small rods, usually quite 

 short, so that they can be mistaken for diplococci. The length 

 is however often rather variable but the thickness is fairly 



