136 IOWA ACADEMY OF SCIENCES. 



Very few attempts have been made to study our local bac- 

 teriological floras. It is indeed a very difficult matter. 



The following works describe Chromogenes: 



Saccardo: Sylloge Pungorum VIII. 



Sternberg: Manual of Bacteriology. 1892. 



Trelease: Observations on several Zoogloea (Studies Biol. 

 Lab. of the Johns Hopkins University). 1885. 



P. & G. C. Prankland: Micro-organisms in Water. 1894. 



Adametz: Die Bakterien der Trink-und Nutzwasser. Mitth. 

 der Oester Versuchstation fur Brauerei-und Malzerei in Wien, 

 1888. Heft 1. 



Jordan: A reporfc on certain species of bacteria observed in 

 sewage. Rep. Mass. State Board of Health, 1888-1890, plate II. 



Eisenberg: Bakteriologische Diagnostik. 1888. 



Welz: Bakteriologische Untersuchnyer der Freiburger Luft, 

 Zeiritschrif t fur Hygiene XI, p. 121. 



No attempt will be made to give description of common 

 species found here at Ames, simply a record of their occurrence 

 including some laboratory observations. 



Micrococcus cyanogenus. N. SP. 



Source. — During the latter part of May, 1894, a foreign blue 

 color was observed on an old milk culture of an organism 

 obtained from cheese; later the same was found in an old milk 

 culture of Bacillus aromaticus. A transfer from the first milk 

 tube was made to another tube of sterilized milk, the typical 

 color appearing in three or four days. The organism was sep- 

 arated by pouring plates of agar. 



Morphology. — A small micrococcus occurring singly or in 

 groups; motility not determined. An aerobic liquefying 

 micrococcus. 



Agar. — Nearly colorless, with a slight tinge of blue, produc- 

 ing an irregular film on surface, growing at temperature of 

 room. 



Gelatin. — A creamy white layer not spreading on surface, 

 soon liquefying, forming a funnel-shaped area, later the 

 medium was liquefied with a creamy white sediment in the 

 bottom of the tube. 



Milk. — Sterilized milk inoculated produces in three days a 

 slight blue layer on surface, which increases in intensity, 

 becoming quite blue for one- third of an inch on the seventh day. 

 On the eighth day it appeared rather muddy; on the ninth day 

 only a faint blue color remained; it coagulated milk with a 



