11 



claim in different ways to have carried out more thorough 

 investigations than those which at present exist, and also to 

 have suggested fresh points of view. 



A very important point in all investigations relating to the 

 occurrence of Pfeiffer's bacillus is the technique of cultivation 

 particularly the constitution of the nutritive medium itself. 

 As there have latterly been introduced a large number of new 

 nutritive media for this microbe, media which to some extent 

 constitute a considerable advance, and since no connected cri- 

 tical review has hitherto been attempted dealing with all these 

 media and with the technique of cultivation in its entirety I 

 have felt impelled to try to give such a review, although it is 

 a little outside the scope of the principal theme of my work, 

 but partly also in connection with my own experience in 

 Ihis field. ! ! 



Perhaps I should expressly state that it has not been 

 my purpose to undertake an investigation of the biology of 

 the haemoglobinophilic bacteria in general and particular regard 

 has therefore not been taken to such points as were not so 

 suitable for the classification. Still less it has been my object 

 to deal with the whole question of the bacteriology of in- 

 fluenza to say nothing of the pathological anatomy, clinical 

 aspect, and epidemiology of the disease. 



I must express my best thanks to my Chief, Dr. Th. 

 Madsen, for the excellent facilities for working put at my 

 disposal and for the help he has given me in various ways 

 in my work. I am also indebted to Prof. Oluf Thomsen for 

 urging me to take the subject up, for much good advice, and 

 for the interest with which *he has followed the work espe- 

 cially in the early and most difficult period. 



Through the liberal and sympathetic attitude which the 

 army medical corps has consistently displayed towards the 

 Serum Institute it has been possible to undertake investiga- 

 tions of considerable extent in the army both among influenza 

 patients and healthy soldiers. For permission to do this I 

 must express my hearty thanks first and foremost to General 

 Ammentorp of the army medical service, and also to the Chiefs 

 of the garrison hospital, particularly to Dr. Knudsen (Staff- 

 Doctor) and Dr. SchiSdte (Senior-Doctor). 



I have also been in a position to carry out extensive inve- 



