1296 



MANUAL OF DETERMINATIVE BACTERIOLOGY 



The strains, like the parent organism, 

 are strictly anaerobic and the cultures 

 have the characteristic odor of the parent 

 strain. 



It was observed in slide cultures that 

 the L type of colonies develop from large 

 round forms which were produced in the 

 cultures of the parent organism by grad- 

 ual swelling of the bacteria. 



In cultures of eight pleomorphic strains 

 of Bacteroides, the L type of colonies 

 developed in three strains under ap- 

 propriate conditions. The bacteria 

 swelled into large round bodies in all eight 

 strains. The serological properties of the 

 L strains have not thus far been studied. 

 Neither the parent organisms nor the L 

 type strains had any pathological effect on 

 laboratory animals. 



3. Pleuropneumonia-like organisms in 

 a species of Flavobacterium. (Dienes, 

 Jour. Bact., U, 19-i2, 37.) 



Tiny colonies entirely similar in ap- 

 pearance to young Li colonies were iso- 

 lated from the cultures of a species of 

 Flavobacterium . 



The bacterium when freshly isolated 

 produced two types of colonies on blood 

 agar plate ; large colonies consisting of 

 small regular bacilli and tiny colonies in 



which the bacteria became pleomorphic 

 and swelled up to form large round bodies. 

 The tiny colonies after 48 hours of incuba- 

 tion became autolyzed, and one or several 

 L type of colonies started to grow under 

 them. These colonies could be trans- 

 planted and gave abundant growth for 

 two generations, but always died out in 

 the third. 



Bacterial forms were not reproduced 

 either on agar or in broth. 



The L type of growth was not patho- 

 genic for mice though the parent organism 

 was highly virulent. 



4. Development of tiny colonies in 

 other bacteria. 



The development of tiny colonies simi- 

 lar in appearance to young colonies of the 

 pleuropneumonia group has been ob- 

 served in cultures of Escherichia coli, 

 Haemophilus influenzae, and Neisseria 

 gonorrhoea (Dienes, Jour. Bact., 44, 1942, 

 37; Proc. Soc. Exp. Biol, and Med., 44, 

 1940, 476). In all cases preceding their 

 development, the organisms ot the parent 

 strains swelled into large round bodies, 

 and in Escherichia coli and Haemophilus 

 influenzae the development of the L type 

 of colonies from these large forms was 

 observed. Thus far these tiny colonies 

 have not been isolated in pure cultures. 



