On Certain Bacteria from the Air of New York City. 349 



Growth yellow. 



Large ilicroeocci 19 



^linute [Micrococci 20 



Growth pinkish thin 21 



Nitrate reduced . . .• 22 



Lactose-litmus not changed or made blue. 

 Milk coagulated. 



Growth orange 23 



Growth yellow 24 



GroAA-th white 25 



Milk not coagulated. 

 Motile. 



Orange 26 



Pink 27 



Not motile. 



Orange 28 



Pink 29 



Yellow. 



Growth granular, a normal precipitate in broth. 



Bright lemon yelloAv 30 



Paler yellow 31 



Pale creamy yellow 32 



Growth forming surface skin, wTinkly 33 



12. Micrococcus cremoides aureus n. sp. 



Occurrence. Obtained by Dr. Freeman from the air of a barn where a cow was 

 being milked. 



Jlorpholoffij. Micrococci 1-1. 25 /< in diameter, associated irregularly. 

 , Biology. Gelatin is raiiidly liquefied ; the surface colonies on gelatin plates 

 are somewhat peculiar ; in the cups of liquefaction which are quickly 

 formed, masses of opaciue orange flocculi settle in a ring shape about a 

 clear central area, giving the appearance of an indented margin. Lique- 

 faction sets in much later with the deep colonies. Thej' appear spherical, 

 light yellow and opaque.; Milk is quickly coagulated, forming a solid 

 curd which is slowly dissolved. Eosolic acid not changed. Lactose-lit- 

 mus is quickly reddened. The growth on agar is narrow, shining, the 

 edges uneven, finely lobed, orange color. The lobed edges are rather 

 characteristic. On glycerine agar the growth is scarcely chromogenic, 

 being very nearly white, biit the normal color is regained when transfen'ed 

 to ordinary agar. At375°C. also the growth is not chromogenic. In 

 broth there is a slight surface growth beside a pale orange sediment. 



Remarks. This species is to be regarded as a varietal form of the following : 



13. Micrococcus cremoides (Zimmermann). 

 Occurrence. (1) In the air of the college hallway. (2) In the air on 59th St. 

 Morpliology and biology as in No. 12, but the growth cream-colored instead of 



orange. On glycerine agar and at 37^° C, the growth is white. 



AXNALS N. Y. Acad. Sci., VIII., May, 1895.— 25 



