On Certain Bacteria from the Air of New York City, 373 



100. Bacillii!^ inefxeiifericiis fusciis (Fliijifie). 



Occurrence. (1) From tlie colle<i;e collection. (2) " Bacillus disciformans," 

 from Krai's laboratory. (3) A contami nation in a milk culture of No. 

 10. 



Blorphology. Eather square-entled bacilli, .5X-9-4//, singly or in chains, mo- 

 tile, form spores. 



Biology. Gelatin (juickly licjuetied, nitrate only ijartially reduced, often only 

 very slightly; lactose-litmus not reddened, rosolic acid not changed. 

 Growth on agar soft, when moderately old pale creamy or ocherous in 

 tint, inclined to be lobed on the edges. Forms a crusty partial skin on 

 broth. 



101. Bacillus 111. fii§cus graiiiilatii!i<( n. sp. 



Occurrence. Abundantly in a jar of "sterilized milk " with No. 1. 

 Morphology and biology. As in No. 100, but the growth on agar is rather 



coarsely granulated, and nitrate is completely reduced in twenty-eight 



days. 



102. Bacillii!^ m. fuscu§ com^istens n. sp. 



Occurrence. A contamination in a milk culture of No. 10 with No. 100. 



Morphology and biology. As in No. 100, but little wandering colonies were 

 seen in lactose-litmus gelatin in the unlitjuefied part of the medium as in 

 B. proteus vulgaris, the bacilli in the chains were separated by well- 

 marked sijaces and the gi-owth on agar was creased and irregular, the 

 edges turning down, almost cutting into the surface of the medium, and 

 was very coherent and difficult to plant. For the hanging drop, it was 

 necessary to break up the growth with two needles. 



Remarks. Nos. 101 and 102 may be varieties of No. 100. 



103. Bacillus pyocyaiieus (Gessard). 



Occurrence. " B. pyocyaneus " from the college collection. 



3Iorphology. Small rounded bacilli .SX-^-l/^, singly or in short chains ; mo- 

 tile. 



Biology. Gelatin (juickly liqiiefied, nitrate completely reduced, rosalic acid 

 rather deepened in color, lactose-litmus made blue. 



104. Bacillus lactis erj throgeiies (Hueppe). 

 Occurrence. (1) From the college collection. (2) " Bacillus versicolor " from 



the college collection.* (3) Thirteen times in the air of the college 



hallway and the yard. 

 Morphology. Very short bacilli, .6-.9X-9-l|W, singly in twos or short chains ; 



not motile. 

 Biology. CJelatin quickly liquefied, milk apparently coagulated but Avithout 



forming a curd on boiling, nitrate reduced completely, or more rarely 



* Dr. Prudden's. description of B. versicolor seems ratlier to apply to No. IO.t and his 

 name has i>recedence over Zimmermann's. Probably both forms were before him and the 

 more (luickly liquefying one got preserved as the typical culture. 



