368 



Scientific Proceedings (124). 



Group IV, 70 per cent. The highest incidence for all groups was 

 during the months of January, February, and March, with a de- 

 cided drop in the late spring and summer months. It is inter- 

 esting to note that during these four years, no Group II pneumo- 

 coccus cases, in a series of 40, occurred in the months of June, 

 July, and August. But 12.9 per cent, of the cases (93) belonging 

 to Group I, 8.2 per cent, of cases (no) belonging to Group III, 

 and 8.7 per cent, of the cases (570) belonging to Group IV, oc- 

 curred during these summer months. 



Further analyses of the data mentioned in the foregoing pre- 

 liminary report are in preparation, the results of which we hope 

 to report more fully later. 



179 (1926) 



The hemolytic properties of the pneumococcus. 



By JULIA A. W. HEWITT and L. W. FAMULENER. 



[From the Pathological Laboratory, St. Luke's Hospital, New York 



City.] 



Recently an interesting phenomenon was observed in culture 

 plates made with the blood from a fatal case of septicemia with 

 meningitis, which followed mastoiditis. The blood culture after 

 24 hours' incubation showed a considerable number of character- 

 istic green colonies which proved to be pneumococcus, Group IV. 

 One of the culture plates which had been used for demonstration 

 purposes before a class of students was stored in the ice box to be 

 preserved for a later section. Some days later, upon its removal 

 from the refrigerator, it was found that marked zones, simulating 

 hemolysis, had appeared about the colonies, giving an appearance 

 almost identical to that produced by hemolyzing types of strepto- 

 cocci. In our previous experience with pneumococcus blood- 

 culture plates, no hemolyzing effect of this nature had been noted, 

 although no continued observation under similar conditions had 

 been followed. The standard reference- and text-books on 

 bacteriology consulted failed, with one exception, to note that 

 pneumococcus colonies might produce hemolysis in blood-agar 

 plates. Zinsser 1 states that hemolysin production, which occurs 



1 Hiss-Zinsser-Russell, "Textbook of Bacteriology," 1922, 5th Ed., p. 445. 



