218 APPLIED BACTEEIOLOGY 



Other organisms belonging to this group are the Staphy- 

 lococcus pyogenes citr&ws, the Staphylococcus cereus aureus, 

 Staphylococcus cereus citreus and the Staphylococcus cereus 

 albus, all of which are so named from the waxen appearance 

 of their cultures. 



Bacillus Pyocyaneus. — It appears that there are two 

 organisms found in blue and green pus, only one of which 

 possesses true pathogenic properties. 



They are separately described by Sternberg as the 

 ' bacillus of Gessard ' and the 'bacillus of Ernst '; the former 

 of them seems to be pathogenic, while the other may be a 

 harmless chromogenic saprophyte. It is the latter which 

 produces the ' chameleon phenomenon.' 



In a paper by E. P. Williams and Kenneth Cameron 

 {Jov/rnal of Pathology and Bacteriology, January, 1896) 

 the authors give an account of some cases of fatal disease 

 in children in which bacilli presenting the characters of 

 both Gessard' s and Ernst's bacilli were isolated and exam- 

 ined by them ; they further state that from the facts 

 observed by them it seems probable that these bacilli are 

 capable of many variations in form and colour production, 

 according to their environment, and that further experi- 

 ments will prove Gessard to be correct in his opinion that 

 they are but varieties of races of the same bacillus. 



Ulcerative Endocarditis, Acute Suppurative Periostitis, and 

 Osteomyelitis. — These and other suppurative conditions are 

 caused by the pyogenic cocci and streptococci. 



