ON SOME NEW MICRO-ORGANISMS OBTAINED FROM AIR. 
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Appearance in Cultivations. 
Gelatine. —After four days liquefaction has commenced at the top of the needle- 
track, forming a round depression, the bottom of which is filled with a white cloudy 
liquid. After nine days the liquefaction has extended across the whole tube to a 
depth of half-an-inch. The liquid is turbid and has a tough, greyish, wrinkled pellicle 
upon its surface and a flo.cculent deposit at the bottom. The lower part of the needle- 
track does not exhibit much alteration even at this stage. Ultimately the whole 
contents of the tube becomes liquid. (See Plate 19, No. 6a.) 
Agar-agar. —The growth is but little characteristic. It forms a moist, shining, 
greyish-wliite surface expansion, which rapidly extends over the whole agar-agar. 
Broth. —After nine days (August 7—16, 1886) the liquid is turbid near the surface 
and clear below; there is a dirty-white flocculent deposit at the bottom, and a thin 
granular pellicle on the surface. Subsequently the liquid becomes clear, the pellicle 
remaining on the surface. 
Appearance on plate-cultivation. —In three days the colonies are visible to the 
naked eye as small white dots, the surface-colonies exhibiting a slight flocculence, 
which indicates the commencement of liquefaction ; as the colonies increase in size, 
liquefaction of the gelatine slowly proceeds. 
Under a low power (x 100) the colonies in the depth of the gelatine are seen to 
have a smooth edge, which is irregular in shape and encloses granular contents. 
The surface-colonies exhibit a very fine thin film of irregular shape, extending from 
a small centre, indicating the spot where the colony first reached the surface and 
began to liquefy. (See Plate 19, No. 6d.) 
The characteristic differences between this organism and Bacillus subtilis will be 
pointed out after the latter has been fully described. 
10. Bacillus Cereus. 
Occurrence, —This was found producing a large liquefying colony on a gelatine-dish 
which had been exposed to the air in a cow-shed. 
Microscopic appearance.— The bacilli are from 3'4 to 12/x in length. There are 
also seen thickened forms about 3'4/r long and 1'7 g wide. The ends of the bacilli 
are generally slightly rounded, whilst some are almost quite square. The bacilli form 
threads which are very variable in length, some being composed of ten segments or 
more. 
Spore-formation was also observed as seen in the Plate. (See Plate 20, fig. 3, No. 3a.) 
In a drop-cultivation the following changes were observed to take place :—- 
When examined directly after inoculation from an agar-agar cultivation, there were 
visible isolated bacilli, many of which contained a single spore, and free spores were 
also present ; there was practically no movement taking place. Within 12 hours 
