16 



rature is given in the form of a collection of short summaries 

 of the individual authors' works (pp. 24 — 40). 



Since the question of the occurrence of Pfeiffer's bacilli in 

 the blood and various internal organs of man, and its 

 power of multiplying in animal experiments and of passing 

 into the blood-stream, has been the subject of rather varying 

 interpretation, this is subjected to analysis (pp. 40 — 45). 



After this question, which is important for the interpreta- 

 tion of the occurrence and classification of Pfeiffer's bacilli has 

 been discussed, the way is open for dealing with the „i n t e r - 

 nal classification" of this bacterium, that is to say the 

 question of mutual differences among the strains. 



Firstly the morphology is dealt with (pp. 46 — 48), then 

 the biochemical reactions of the organism (pp. 48—51); 

 finally the results of the serological investigations 

 (pp. 51 — 56) and a few supplementary comments (pp. 56—58). 

 Since the investigations into the occurrence and classifi- 

 cation of Pfeiffer's bacillus were made principally with parti- 

 cular reference of the question of its significance in 

 influenza, and as this is the most important of the que- 

 stions which arise in connection with Pfeiffer's bacillus, I have 

 considered it appropriate to make this the subject of dis- 

 cussion both in connection with the account of Pfeiffer's in- 

 vestigations and the review of the occurrence and classification 

 of the bacillus. In order that this discussion shall not be too 

 incomplete the most important of the other facts to which 

 significance has been attributed in this connection are also 

 shortly referred to (pp. 58 — 64). 



In the account given of the classification of Pfeiffer's ba- 

 cillus several of its characteristics are mentioned. A complete 

 presentation of the biology of this microbe has however not 

 been attempted and various facts interesting in themselves are 

 therefore entirely omitted as they have no particular impor- 

 tance with respect to the points at issue. Several of these 

 facts will be referred to in discussing my own investigations. 

 The same applies to the question of the distinction between 

 Pfeiffer's bacillus and other nearly related species, especially 

 other haemoglobinophilic bacteria. 



