W. L. HOLM AN iii 



PNEUMOCOCCUS 



The pneumococcus is usually considered a rather delicate organism in culture 

 media, but apparently it may have a striking antagonistic effect on the staphylo- 

 coccus. Gromakowsky' discovered in eight sputum cultures a coccus which had a 

 definite restraining action on the staphylococcus. This coccus resembled the pneumo- 

 coccus in morphology, but he considered it different. Mixed with eight different 

 strains of staphylococci and after twenty-four hours' incubation, transfers to agar 

 gave no growth of the staphylococcus. It was irregular in action and also was an- 

 tagonistic to streptococci from abscesses. Ahvisatos,^ working with twenty-eight 

 strains of well-identified pneumococci and three strains of Staphylococcus albus, no- 

 ticed, when the forms were mixed, interesting phenomena on ascites agar plates. 

 Curious clear zones appeared about the colonies of the pneumococci, and the edges of 

 the staphylococcus colonies were irregular and suggested the action of bacteriophage. 

 These zones varied in size, and if enough pneumococci had been added no growth of 

 staphylococcus occurred. He never found mixed colonies. Neither the virulence nor 

 the agglutinating type of the pneumococcus was related to the extent of the phenom- 

 ena. There was no demonstrable change in the cultures of either of the bacteria after 

 these contacts. Living, growing pneumococci were necessary and filtrates were nega- 

 tive. Eight strains of hemolytic, five of viridans, and one of mucosus streptococci 

 gave negative results. In these cases mixed colonies were frequent, and he suggested 

 that this characteristic might be used to differentiate pneumococci from closely sim- 

 ilar streptococci. 



COLON-TYPHOm GROUP 



The antagonistic effect of soil bacteria against pathogenic forms has been exten- 

 sively studied. The early work of Frost^ is important and includes the literature to 

 that date. Limitation of space forbids a further discussion of this interesting subject. 

 Fecal bacteriology, particularly of the colon-typhoid group, is replete with examples 

 of supposed antagonism. It has long been held that the presence of slow lactose fer- 

 menting B. coli, so frequently observed in stool examinations, is due to this phenom- 

 enon (von Jeney"), and Henningson^ gave examples of inhibition of gas production 

 and proposed the name B. coli anaerogenes for these. PrelP and many others have 

 studied such defective strains. Nissle,^ having observed an inhibitory action in cer- 

 tain stools seeded with B. typhosus, studied the antagonistic index of the B. coli to 

 B. typhosus with various strains of the former. The difference seemed correlated with 

 lactic acid production. The active coli strains also were inhibitory to other coli 

 strains. He therefore gave these active cultures in capsules to persons carrying in- 

 efficient B. coli strains and reported good results. R. P. Smith* found that B. coli 



' Gromakowsky, D.: ibid., Orig., 32, 272. 1902. 



^ Alivisatos, G. P.: ibid., 94, 66. 1925. 



3 Frost, W. D.: J. Infect. Dis., 1, 599. 1904. 



* von Jeney, A.: Ztschr.f. Hyg. u. Infektionskrankh., 100, 47. 1923. 

 sHenningson, B.: ibid., 74, 253. 1913. 



^Prell, H.: CentralU.f. BakterioL, I, Orig., 80, 225. 1917. 

 7 Nissle, R.: Deutsche mcd. Wchnschr., 42, 1181. 1916. 



* Smith, R. P.: J. Path. b° Boot., 26, 122. 1923. 



