IOWA ACADEMY OF SCIENCES. . 137 



blue liquid on top. The curd was dissolved slowly. In twenty- 

 five days the process was completed, excepting a small portion 

 in the bottom of the fl isk. 



Dunliani s 'peptone solution. — No color produced; > the medium 

 became cloudy, which was ia no way characteristic. It failed 

 to grow in Duaham's rosalic acid solution. 



Several blue organisms have been described. 



Bacillus cyanogenus is a well known inhabitant of milk. This 

 is a non-liqaefyicg, actively motile bacillus. Has not been 

 found here at Ames. Gessard has shown that in presence of 

 an acid it produces an intense blue color, and in milk not 

 sterilized containing lactic acid germs, a sky blue color is 

 produced. 



Jordan has also described a Bacillus cyanogenus, which is less 

 motile formiag a deep brown color on potato, but he says 

 undoubtedly Bacillus cyangenus. Beyerinck^ has also described 

 a blue organism obtained from cheese, the Bacillus cyaneo-fuscus. 

 The original paper has not been seen but according to the 

 description given by Sternberg this is a small bacillus 0.2-0.6 

 u. long and one half as thick. It is an aerobic liquefying 

 motile bacillus, and when cultivated in a solution contaiuing 

 one-half per cent of peptone the culture media acquires at first a 

 green color, which later changes to blue, brown and black. 

 Subsequently the color is entirely lost. More recently Wm. 

 Zangemeister^ has described a biciJus cyaneo-flaorescens. 



This species is in many respects similar to Bacillus cyanogenus. 



It is however somewhat shorter and very actively motile. 



Gelatin is not liquefied and the bright greenish fluorescent 

 pigment dfliu&es through it. 



Oar species also came from cheese and the blue color disap- 

 pears, but the organism in question never produces a black 

 color. The species so far as we have been able to determine 

 is new, and we have therefore given it the name of Micrococcus 

 cyanogenus. 



Staphylococcus pyogenes, Ogston var. aureus Rosenbach.— This, 

 the most common of the pyogenic micrococci has been found 

 quite frequently here at Ames. It has at different times been 

 isolated from ordinary carbuncle, fistula, dirt under the finger 

 nails, etc. It has been found more commonly in suppurative 

 abscesses than any other organism. It is pathogenic to mice 



^Sternberg: Manual of Bacteriology p. 72". 



SKurze Mitteilungen uber Bakterien der-blauen Milch. Centralblatt f. Bakt. u 

 ParsitcDkunde. Erste Abt., XVIII, p. 321. 



