IOWA ACADEMY OF SCIENCES. 
125 
feran has an article which is the result of a comparative and 
experimental study of bacilli producing red pigment. 
Hueppe has done a great deal in identifying species. 
He was the first to isolate /:>. violaceus laurentius from the 
Lawrence sewage experiment station in 1890. 
Chester in his classification recognizes: 
B. violaceus laurentius , 
B . violaceus lutetiensis , 
B . violaceus berolinensis , 
B. violaceus ox Ps. janthina , 
B . violaceus sacchari, or B. ceris, a violet colored pigment noted 
in old milk cultures and whose habitat is the air. 
The organism that has been studied in connection with 
this paper Doctor Pammel isolated in March, 1904, from a 
well near the campus. It was identified as B. violaceus. A 
month later one of the students isolated it from a sample 
taken from the creek running through the college park and 
receiving sewage from adjoining farms. At the same time 
I was making a study of the biological conditions of the 
Iowa State College sewage disposal plant and isolated a 
violet organism from the effluent. At that time a cultural 
study was made and the growth was noted as follows: 
Source. — Brought to the laboratory from a well near the 
campus. Found in effluent of sewer. Found also in creek. 
Morphology. — Short, slight bacilli with rounded ends. 
Often occurs in pairs, sometimes in chains of four or five. 
No spore formation observed. 
Habitat. — Water. 
Motility. — Actively motile. 
Color . — Produces violet color on top of slant and stab 
cultures. No color along stab; hence needs oxygen for 
production of pigment. 
Agar Stab. — Vigorous growth along stab. A white spot 
appears on top which turns violet in color. The colony 
spreads in a thin irregular expansion. It covers the top of 
the medium and the color changes to black or dark purple. 
This description agreed with that given by Chester and 
we conclude that the organism is a variety of the B. 
violaceus. 
