EFFECT ON MORPHOLOGY OF MICROORGANISMS 213 



The relation between antibiotics and bacteriophage has attracted con- 

 siderable attention. Gratia (345) observed a definite relation between 

 the action of lysozyme and the liberation of bacteriophage. The action 

 of antibiotic agents, however, usually exhibits a marked distinction from 

 that of bacteriophage (218, 344, 634). Filtrates of cultures of homolo- 

 gous bacteria are able to inactivate the anti-coli phage j at 27° C, the 

 inactivation is proportional to the phage and filtrate concentration j at 

 0° C, to the square root of the latter (232). Based upon the formation 

 of iso-antagonistic substances, a method has been suggested (121) for 

 the differentiation of bacteria belonging to the typhoid group. 



EFFECT OF ANTIBIOTIC SUBSTANCES UPON THE 

 MORPHOLOGY OF MICROORGANISMS 



Emmerich and Saida (238) were the first to report that anthrax bac- 

 teria undergo morphological changes as a result of the action of pyocya- 

 nase. Since that early work, the effect of bacterial filtrates upon cell 

 multiplication and cell growth has been made the subject of many in- 

 vestigations. It was reported (378), for example, that no complete ces- 

 sation of the fission process of bacteria results from the action of the 

 substance, but that growth itself is checked, the action being nonspecific 

 as far as bacterial species are concerned. The conclusion was reached that 

 this phenomenon is due to the production and accumulation of metabolic 

 products injurious to growth. Nonspecific antibiotic substances were 

 demonstrated (6s6) in filtrates of bacteria. They not only injured 

 growth of other bacteria but prevented the production of the ectoplas- 

 mic antigen. These substances could be partly removed by the use of 

 adsorbents. 



The morphology of bacteria is greatly influenced by the presence of 

 other organisms or their antibiotic substances. In the case of diphtheria 

 bacteria this is accompanied by a reduction in virulence (406). The spe- 

 cific effect of the antagonistic B. mesentericus upon the morphology of 

 antagonized bacteria has been established by Pringsheim (705). The 

 antibiotic substances produced by actinomycetes were shown (80) to 

 affect the growth of B. mycoides as follows: cell division is delayed} the 

 cells become elongated, reaching enormous size and assuming most pe- 



