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



39. Bacillus siibochraceiis n. sp. 



Ofcitrrence In the air of the college liallway. 



Morphology. Rather small bacilli, .7X1-5/', not motile or spasmodically so, 

 singly or in short chains. 



Biology. Milk is not coagulated at first, but in tAveuty-six days a coagulum 

 was obtained on boiling; only very slight nitrate reduction. Litmus is 

 reddened at first, but in thirty-five days the red begins to disappear and 

 is replaced by purple, still later by blue (ninety days). Growth on 

 solid media is translucent with more or less of an ocherous tint, some- 

 times almost light orange (lactose-litmus gelatin). There is a slight 

 surface growth on broth ; rosolic acid is deepened in color. Surface colo- 

 nies on gelatin are clear, rather iiTCgular, slightly veined; the deep ones 

 are round, dusky yellowish. 



40. Bacillus doinesticus n. sp. 



Occurrence. In the air of an apartment house on "West 69th street. 



Slorphology. Rather small rounded bacilli, .5X1/^, mostly in pairs, not 

 motile. 



Biology. Nitrate is reduced rather slowly, but completely in seventeen days. 

 A slight pink tint may be seen in the surface of milk. Litmus is made 

 red but in fifty days begins to be replaced by blue. Growth on solid 

 media at first white, but later shining light yellow, slowly spreading. 

 Grows well on potato and glycerine" agar. The surfa<?e colonies on gelatin 

 are larger than the deep ones, thin, granular yellowish centrally with 

 even edge. 



Ecnuirks. Seems near B. striatus flavus von Besser, but the cells are not cui'ved 

 and I did not notice any striations. 



Also near No. 42, but the nitrate is much more strongly reduced. 



41. Bacillus fluoresceus tenuis (Zimmermann). 



Occurrence. " ]\Iicrococcus versicolor " from the college collection. 

 Morphology. Rather short bacilli, mostly in short chains, .6X1-2/^ actively 



motile. 

 Biology. Nitrate quite strongly reduced but not comj)letely. Growth on agar 



translucent white with a green fluorescence in the medium; lactose-litmus 



permamently reddened. 

 Bemarks. See remarks under No. 35. 



42. Bacillus aiuabilis n. sp. 



Occurrence. In the air of the college hallway. 



3Iorp]iology. Very short l)acilli, often nearly spherical, .7X-8-1 « singly or in 



irregular chains or masses; not motile. 

 Biology. Nitrate slightly reduced. On agar a narrow translucent white streak 



with pale yellow tint; surface colonies rather large, translucent, yellomsh, 



on potato a very thin growth, In-ight yellow with ill defined edges- 



Produces no iudol ; rosolic acid not changed. 

 Bemarks. The cultures died during the summer vacation. 



