ON SOME NEW MICRO-ORGANISMS OBTAINED FROM AIR. 
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instance a white deposit, which later on becomes of a pinkish colour, whilst at the 
surface the colour is visible much sooner. 
Appearance on plate-cultivation .—After two days the colonies are seen to the 
naked eye as circular depressions, each having a red centre. Under a low power 
(X 100) the less-developecl colonies in the depth of the gelatine are devoid of red 
colour; they are finely granular, with a very irregular contour. (See Plate 20, 
No. Id.) The surface-colonies, on the other hand, have a distinctly red nucleus 
surrounded by a very thin and finely granular brownish growth having a very 
irregular contour. (See Plate 20, No. Id.) No. le represents the appearance of the 
colonies to the naked eye. 
III.—SACCHAROMYCES. 
We have found two varieties of Saccharomyces in the air, the one colourless, and 
the other producing a red pigment. They are both of very frequent occurrence. 
1. Saccharomyces Liquefaciens. 
This organism produces very characteristic star-shaped liquefying colonies on 
gelatine-plates which have been exposed to the air. 
Microscopic appearance. —The individual cells are oval and 7 and even 9p in 
length, and from 3 to 5g in width. They appear only to bud from the apex, and 
frequently there are twin buds from the same apex of the parent cell; occasionally 
they are seen hanging together in long strings. (See Plate 19, fig. 1, No. Id.) 
Appearance in Cultivations. 
Gelatine. —After a few days the needle-track below the surface exhibits small 
feathery centres in its lower portion, whilst in its upper portion the track is 
continuous and throws out hair-like lateral extensions of increasing length into the 
adjacent gelatine. On the surface there is a depression filled with white, cloudy, 
liquefied matter. Later on, the liquefaction extends across the tube, and ultimately 
involves the whole of the gelatine. (See Plate 19, No. la.) 
Agar-agar. —Forms a shining surface-growth exhibiting radial marking from the 
central puncture. The surface is very faintly pink in colour. The track of the 
needle beneath the surface exhibits beautiful feathery lateral extensions. (See 
Plate 19, No. lb.) 
The growth both in gelatine and agar-agar is exceedingly characteristic. 
Broth.— After nine days (August 7—16, 1886) the liquid is clear, with a dirty-white 
deposit at the bottom. 
Appearance on plate-cultivation. —The colonies when young appear as small cloudy 
centres to the naked eye. As they increase in size they assume a star-shaped 
appearance, the rays of which gradually extend and liquefy the gelatine in a highly 
characteristic manner. 
