ON SOME NEW MICRO-ORGANISMS OBTAINED FROM AIR, 
269 
Appearance in Cultivations. 
Gelatine. — After four days (August 6—10, 1886) there is a slight surface 
depression filled with semi-liquid cream-coloured matter; even after sixteen days the 
semi-liquefaction has but very slightly increased. 
Agar-agar. It forms a surface shining growth of light-orange colour. 
Broth .—After nine days (August 7—-16, 1886) the liquid is clear, free from 
pellicle, and has a dirty-white deposit at the bottom. 
Appearance on plate-cultivation .—After four days the surface-colonies are visible to 
the naked eye as pin-heads of yellowish colour. Under a low power (X 100) they 
are seen to be generally round (see Plate 19, No. 3b), the more developed colonies 
showing a finely granular edge, whilst the less developed have a smooth edge. 
Note. —The dark semi-circular edge seen in the figure indicates the depression 
produced by the colony on the surface of the gelatine. 
9, Micrococcus Rosaceus. 
Occurrence. —We have frequently met with this organism in the course of our 
experiments on air; we have also compared it with a cultivation which was brought 
by one of us from Dr. Koch’s laboratory in Berlin. On gelatine plates or dishes which 
have been exposed to the air, it produces small, smooth, shining, bright pink expan¬ 
sions. 
Microscopic appearance .—Under a high power (x 1,000 or 1,500) the cocci are 
seen to be very variable in size, the largest being as much as 2'5/r in diameter; the 
larger forms exhibit a well-marked division. (See Plate 17, fig. 4, No. 4a.) 
Appearance in Cultivations. 
Gelatine. —It forms a shining, smooth, pink expansion on the surface, whilst the 
needle-track below remains almost undeveloped. As the cultivation becomes older, 
the margin assumes a radiated appearance. Still older cultivations frequently exhibit 
slight liquefaction. 
Agar-agar. —Forms a smooth, bright-pink surface-expansion devoid of any further 
characteristics. 
Broth .—After nine days (Aug. 7-—16, 1886) the liquid is clear, free from pellicle, and 
exhibits a pink deposit. 
Appearance on plate-cultivation.—To the naked eye the more developed colonies 
appear as pin-heads on the surface, and are bright-pink in colour. Under a low 
power (X 100) they are seen to be of a distinctly reddish tint, the edge being irregular, 
but smooth ; but as the colonies approach the surface the irregularity diminishes. 
(See Plate 17, No. 4b.) 
