4 MASS. EXPERIMENT STATION BULLETIN 319 



of some typhoid strains. He found that a broth culture may manifest inagglutina- 

 bility, while a suspension of the same strain prepared from an agar slant is agglu- 

 tinable. 



Spontaneous clumping was also observed among typhoid strains by Savage 

 (1901), who emphasized the fact that this phenomenon may be of great practical 

 importance, since it may lead to errors of diagnosis in routine work. An investiga- 

 tion of the conditions necessary for the formation of these clumps revealed that 

 the phenomenon occurred within 24 hours, independent of age of cultures and of 

 scum formation. Organisms suspended in saline solution, peptone-water, and 

 broth exhibited clumping only in the broth. 



Preisz (1904) found that B. anthracis, when cultivated on slightly alkalinized 

 agar, developed papillae or secondary colonies, which appeared as contaminants, 

 and after several weeks might give rise to tertiary colonies. Marked differences 

 in the morphology of the bacilli belonging to the primary and secondary colonies 

 were observed. 



Hiss (1904) observed that Bad. dysenteriae (type "Y"), when subjected to 

 frequent transfer in maltose medium, acquired the property of attacking that 

 carbohydrate more rapidly. 



Steinhardt (1904) was able to demonstrate the influence of serum on the viru- 

 lence of paradysentery and typhoid organisms. Normal horse serum exhibited 

 little influence, while inactive and immune sera reduced the virulence. He isolated 

 a spontaneously agglutinating strain from a typhoid stock culture. The colonies 

 of the agglutinating type possessed a more irregular surface and greater opacity 

 than the stable strain. 



Eisenberg (1906) observed granulation formation in typhoid and other colonies 

 after the addition of egg albumin to the medium. This appearance was obtained 

 only in old cultures. He believed that this type of development was due to the 

 detachment from the colonies of bacilli which penetrated more deeply into the 

 medium and gave rise to small adjacent colonies. 



The investigation of Massini (1907) definitely revealed that a lactose-fermenting 

 organism was derived from a non-lactose-fermenting strain, and that it was 

 absolutely stable. On lactose-fuchsin agar it formed white colonies, but after a 

 short incubation period red papillae developed. This occurred only in the presence 

 of lactose, and the new characters could be removed by subjecting the organism 

 to phenol medium. An homologous antiserum for the white strain agglutinated 

 both the white and red strains to the same degree. Likewise, an antiserum pre- 

 pared against the red organism agglutinated both types. Histological sections of 

 the papillated colonies revealed light and dark streaks which extended throughout 

 the colony mass. Certain layers in the colony stained with different intensities. 



Peckham (1907) was successful in accentuating the proteolytic activity of the 

 typical colon bacillus, and in stimulating indol formation by atypical colon 

 organisms that had been devoid of it, and by typical typhoid bacilli. He also 

 stated that Bad. coli-communis at times possesses pathogenic properties, and 

 that by artificial methods of treatment it may often be brought from a condition 

 of benignity to one of virulence. 



Twort (1907) was able to induce Bad. typhosuni to ferment dulcitol and 

 lactose by cultivating the organism in the respective media and transferring at bi- 

 weekly intervals over a long period of time. Likewise, Bad. paralyplwsum B 

 acquired the power of fermenting saccharose. He concluded that by this means 

 a pathogenic organism may be altered until it gives fermentative reactions charac- 

 teristic of a non-pathogenic member of its group. Furthermore, he suggested 

 that this process may occur in nature. 



