BACTERIUM COLL 249 



I any cases of myelitis, as they can produce such ex- 

 srimentally in rabbits (C. B. xvi, 919). 

 (d) In animals: In septic infections (puerperal fever, 

 septic inflammation of the umbilical cord, etc. ) of cattle. 

 Compare hog cholera, page 252. 



Experimental Observations Regarding Pathogenic 

 Action. — (a) In animals: Just like the Micr. pyogenes, 

 the Bact. coli possessed most variable degrees of virulence; 

 the various morphologically and biologically variable 

 characters are entirely useless for determining anything 

 regarding the virulence. According to Valagussa, the 

 virulence of the colon bacteria from the intestine of ex- 

 perimental animals is greater the sicker the animal. 

 In cats vegetable diet produces considerable increase of 

 virulence of the colon bacteria, milk diet a marked at- 

 tenuation. Subcutaneously the Bact. coli sometimes 

 causes only suppuration, sometimes septicemia ; intra- 

 peritoneal injection of 1 c.c. of bouillon culture, according 

 to Gabritschewsky, is always fatal for guinea-pigs in 

 about fifty hours. Fifty separately isolated Bact. coli 

 cultures behaved exactly alike in this ; bacteria were 

 always present in the heart's blood (C. B. xvn, 833). 

 According to Vallet, cultivation in filtered, sterilized 

 urinal refuse increased the virulence very much (C. B. 

 xiv, 325). 



Immunity and Serum Diagnosis. — Active immun- 

 ization in the usual way is possible. The serum aggluti- 

 nates coli bacteria. According to many writers (for exam- 

 ple, Pfaundler, C. B. xxni, 9, 71, 131), the agglutinating 

 action of the serum is much greater against the coli 

 culture employed in the immunization than against other 

 cultures, and it is even absent against many other cultures. 

 The new form of serum reaction observed by Pfaundler 

 was only observed in the action of serum upon the culture 

 employed to produce the immunity. It consists in the 

 absence of agglutination and the formation of balls of 

 long threads in twenty-four hours. 



(b) In man: Pathologic etiologic observations, which 

 have the significance of experiments, have been made in 

 man with B. enteritidis Gartner and B. morbificans bovis 

 Besenau, which are to be considered as examples of the 



