DISSOCIATION AND TRANSFORMATION 149 



papillae appearing on about the fourth day. When the blood con- 

 tent of nutrient agar fell below 5 per cent, the S colonies ap- 

 peared small and rough, yet were not true R colonies. The same 

 effect was brought about by an alkaline reaction of the medium, 

 but the original characters were restored on transplantation to a 

 more favorable medium. 



In a study of the bile-solubility of Pneumococcus, Atkin 29 re- 

 ported that pneumococci growing in papillae or secondary colonies 

 developing on an autolyzed colony from a point inoculation on a 

 thick serum-agar medium of proper reaction were insoluble and 

 that susceptibility of the variants to the action of bile corre- 

 sponded to the possession by the organisms of autolysin. When the 

 insoluble cocci were subcultured on a fresh serum-agar slant, they 

 regained autolytic properties and bile-solubility. 



Grumbach 563 also studied the details of colony formation accom- 

 panying the varying degrees of pneumococcal dissociation. He dif- 

 fered with Atkin, 29 but agreed with Paul that daughter colonies 

 were not identical with R forms of pneumococci, because they were 

 never truly granular on ascitic agar, they remained bile-sensitive, 

 were fully virulent, and on transplantation developed into "bud- 

 carrying" S colonies. Grumbach found that the ability to produce 

 hemolysis on blood agar and in blood bouillon in forty-eight to 

 seventy-two hours quite commonly ran parallel with the dissocia- 

 tion phenomena. He described the characters of three virulent S 

 strains isolated from pneumonic material that were not aggluti- 

 nated by Type I, II, or III serums. Growing for twenty-four 

 hours on ascitic agar the organisms produced the classical picture 

 of pneumococcal colonies. The thickness of the peripheral ring va- 

 ried, and in one case there was a "wall" formation of the type 

 Buerger and Ryttenberg 169 claimed to have found solely in colonies 

 of streptococci. Grumbach also described a "wing-form" colony 

 which he believed to be similar to that supposed to be caused by 

 phage action on streptococci, and concluded that the same colony 



