On Certain Bacteria from the Air of Neiv York City. 355 



33. 3Ierisiuopedia iiieseiitericiis cornigattis n. sp.* 

 Occurrence. "Staphylococcus pyogenes citreus ' ' from the college collectiou. 

 3Iorpholo(jy. Micrococci .9 u in diameter, associated in great adherent masses 



more or less packeted, breaking apart into twos or single elements. 

 Biolofiy. Gelatin is quickly li(iuelied. On agar, the gi-owth spreads rapidly, 

 and becomes covere<l with a few large wrinkles or folds, traversing the 

 surface in various directions; the color is yellow. On broth, a thick and 

 wrinkled yellow surface skin is formed \vith a slight yellow sediment in 

 the bottom. 



Nox-Liquefyixct Baccilli. 



(Synopsis of species.) 

 La<>tose-litmus reddened. 

 Nitrate not reduced. 



Milk coagulated 34 



Milk not coagulated. 



Actively motile, a gi-een fluorescence 35 



Not motile or spasmodically only. 



Small bacilli 36 



Very large vacuolated 37 



Nitrate rediiced, at least partially. 

 Milk coagulated. 



Lactose-litmus permanently reddened, growth white 38 



Lactose-litmus reddened, later blue, growth sometimes faintly 



ocherous 39 



Milk not coagulated. 



Growth yellow, nitrate completely reduced 40 



A green fluorescence ; nitrate partly reduced 41 



Pale yellow, nitrate slightly reduced 42 



Lactose-litmus made blue. 



Nitrate reduced, at least fairly well ; milk not coagulated. 



Growth dark yellow 43 



Growth pale yellow , 44 



Growth white. 



Grows Avell at room temperature. 



Rosolic acid faded 45 



Eosolic acid not faded. 



Not motile ; 46 



Actively motile. 



Growth thin, transparent 47 



Growth moderately opaque 48 



Scarcely grows at room temperature 49 



* Compare with this No. 107, Bacillus erythrogenes rucjatus. The biological charac- 

 ters of the two are practically alike. Xo. 33 was determined as a Micrococcus, and No. 

 107 as a Bacillus ; but it is one of the shortest bacilli known, so that the differences be- 

 tween these forms are really slight. Xo. 33 was not observed to form any pink color ; 

 but this is not en invariable character of the lactis erythrogenes group. 



