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on the special object of the investigation and will not be dicussed 

 in this connection. Some of the most important points were dealt 

 with on pp. 30—31 and 37. It need only be stated here that 

 Negrette, Olsen (1) Seligmann & Wolf and others had good 

 results in the cultivation of Pfeiffer's bacillus by letting the 

 influenza patients cough on the plates (with Meyer & Ciiie- 

 vitz's (4) „coughing-inoculation method" as a guide), but that 

 this method failed in the hands of Loewenhardt (2), which 

 he explained as due to the fact that the sputum was too 

 tenacious to be distributed in fine droplets. In my experience 

 also the coughing method was greatly inferior to the spreading 

 of the sputum as a means of detecting Pfeiffer's bacillus. The 

 utility of this method ought therefore to be carefully controlled 

 under the given conditions before using it as the chief one. 



The most important rules for the cultivation of Pfeiffer's 

 bacillus may be stated as follows. As far as the examination 

 concerns the occurrence of the bacillus in influenza it should 

 be conducted as early in the disease as possible. As material, 

 sputum and mucus from the naso-pharynx are used. It is of 

 special importance to inoculate the material as soon as possible. 

 Plates should be used which have been previously warmed 

 in the incubator. 



When a larger series of investigations into the occurrence 

 of Pfeiffer's bacillus is to carried out it will be advisable to 

 start with several different media and afterwards adhere to that 

 giving the best results. The special conditions will determine 

 which medium will be best. Fildes agar (for example, pre- 

 pared with horse blood) and agar mixed with haemolysed pigeon 

 blood ought specially to be recommended as media for the 

 isolation of Pfeiffer's bacillus. If we further include ordinary 

 blood agar (heated to a dark red colour) and Levinthal agar 

 the chief types of ^haemoglobin" media will be represented. A 

 good medium is characterized by two things: (1) that when the 

 original culture of Pfeiffer's bacillus grows on it colonies are 

 always formed of the size that ought to be attained on that 

 medium; (2) that a pure culture of Pfeiffer's bacillus inocu- 

 lated on it should always give a good growth. The most 

 suitable incubation time to obtain a good result is presumably 



