A Comparison between Pfeiffer's Bacillus 

 and other „Haemoglobinophilic Bacteria". 



1. Haemolytic, haemoglobinophilic bacilli. 



H aemolytic, haemoglobinophilic bacilli were 

 first described by Pritchett & Stillman and afterwards by 

 Stillman & Bourn, Rivers & Leuschner and Bloomfield (2). 

 These authors describe, in a fairly unanimous manner, these 

 organisms as Gram negative rods which as a rule, though not 

 always, are coarser than Pfeiffer' s bacillus and more inclined 

 to form threads. On blood agar they produce clear haemolysis 

 in the same way as typical haemolytic Streptococci. Like 

 Pfeiffer's bacillus they are haemoglobinophilic and their growth 

 is promoted by other organisms. They only have a slight 

 power of fermenting the various carbohydrates. Only a few 

 of them produce indol. In cultures which are not sub- 

 cullured, they die out still more rapidly than Pfeiffer's ba- 

 cillus. They are principally met with in healthy persons and 

 do not appear to be pathogenic for man or animals. 



Through using media on which haemolysis cannot show 

 itself e. g. „chocolate agar", they have undoubtedly often been 

 confused with Pfeiffer's bacillus. Rivers & Leuschner consider 

 that in future they ought to be regarded as belonging to the 

 group of Pfeiffer's bacilli. There is general agreement that 

 in many respects they resemble them' very much. 



I, also, have found these bacteria widely distributed and 

 exclusively in healthy persons. They were probably present 

 in the earlier inoculations, but on account of the haemolysis 

 produced they were not investigated further. In the inocula- 

 tions of 6. III. 20. haemolytic, well marked haemoglobinophilic 

 bacteria were discovered in 16 out of 200 persons examined. 



