206 



In the inoculations on 14. IX. and 15. X. 20. they were 

 also found but they were not investigated further. In the 

 inoculations on 6.— 10. IX. 21. about 2 / 3 of the 452 plates were 

 examined for these bacteria; they were found in 16 cases. 

 On 17. IX. 21 they were found in 30 out of 230 persons. 

 Further investigation of the strains from the last two series 

 of inoculations showed that on the whole they were decidedly 

 less haemoglobinophilic than Pfeiffer's bacillus. (The reason 

 this was not noticed in the investigation of the 1920 strains, 

 is presumably due to the fact that only the most haemoglo- 

 binophilic strains were taken into account and that a direct 

 comparison between these and Pfeiffer's bacillus was not made). 

 In the later investigations Pfeiffer's bacillus and the haemolytic 

 ones were inoculated simultaneously on agar plates. It was 

 noted (without knowledge of which strains were haemolytic) 

 which cultures gave perceptible growth in the first cultivation 

 on this medium and it was found that they were practically 

 identical with the haemolytic. As Pfeiffer's bacillus and the 

 haemolytic bacilli were thus examined under precisely the 

 same conditions there can be no doubt that the latter really 

 behave rather differently from Pfeiffer's bacillus as regards 

 dependence upon haemoglobin. It was only possible to cul- 

 tivate some of the haemolytic organism's further on agar; in 

 the third culture on this medium only a few strains grew. 

 In a number of cases only one colony appeared which however 

 was sometimes rather large. The addition of ascitic fluid to 

 the agar did not favour the growth of these bacilli in any 

 of the cases, on the contrary it inhibited it so much that 

 there was usually no growth on ascitic agar in the first 

 culture. 



The keeping properties of the haemolytic strains, in my 

 experience, are also distinctly less than those of Pfeiffer's 

 bacillus, a fact which makes it difficult to define more accu- 

 rately the undoubted differences in the dependence upon hae- 

 moglobin between Pfeiffer's bacillus and the haemolytic ba- 

 cilli as well as between different strains of the latter. In this 

 group there seem to be gradual transitions from strains which 

 are very haemoglobinophilic to strains which can grow fairly 

 well without haemoglobin. 



Haemolysis is a character which sharply distinguishes these 



