IOWA ACADEMY OF SCIENCES. 139 



obtained frequently from butter and milk, but the organism 

 undoubtedly came from the air. 



S. aurantiaca Fliigge. — This organism is also quite commonly 

 met, and appears on gelatin and agar plates exposed to the air. 



Bacillus fluorescent Uqaefaciens Fitigge. — Tnis common inhab- 

 itant of water also occurs on potato, milk and butter. Scarcely 

 a sample of water can be plated without; obtaining this 

 organism. 



B. pyocyaneus Gessard. — This has been obtained several times 

 from wounds and Dr. S. Whitbeck obtained a pure culture in 

 open synovial bursa. Inoculation into the peritoneal cavity was 

 followed by death in forty-eight hours. In old cultures there 

 is a gradual tendency for the organism to lose its power of 

 forming coloring matter. Gessard 5 has isolated two pigments a 

 fluorescent green and a blue, the latter called pycoyanin. 



Bacillus prodigionsus Ehrenberg. — This species is well known 

 to most bacteriologists. It has long attracted attention because 

 of the red stains produced on potatoes, boiled bread, and the 

 red color it imparts to milk. According to several investi- 

 gators this organism is not a native to this country. 



The species is however, recorded at Ames by Bassey. He 

 commonly obtained a red organism on sliced potatoes exposed 

 to the air. 



There are of course several red organisms and as the organ- 

 ism was reported before the era of modern bacteriological 

 methods I must therefore express some doubt as to the correct 

 determination of the Bacillus prodigiosus found by Bessey. 

 The senior writer has at various times had cultures of this 

 organism in the laboratory. Thus we had good growing cul- 

 tures in 1889, 1892, but all attempts to make old cultures failed. 

 In 1894 a blood-red colony came up in culture plate. Cultures 

 of this organism had never bean in this laboratory so far as we 

 know. In the spring we had received from Dr. Irving W. 

 Smith, cultures of several species obtained from the laboratory 

 of Johns Hopkins University. The cultures appeared pure 

 but they may have been contaminated. The senior writer 

 observed this organism on one other occasion in the botanical 

 laboratory of the Shaw School of Botany, St. Louis. Cultures 

 of B. prodigiosus were obtaiaed from rotting sweet potatoes, 

 but European cultures were common at the time in the labora- 



5Gessard. De la pyocyanine et de son Microbe. These de Paris, 1882. Nouvelles 

 recherches sur la Microbe pyocyanique. Ann. d VInstitut Pasteur. Vol. IV, 1890, p. 89 

 6Bull. Dept. of Botany, Nov. 1884. 



