ON SOME NEW MICRO-ORGANISMS OBTAINED FROM AIR. 
275 
Appearance in Cultivations . 
Gelatine.- —After four days (August 6 —10, 188G) the needle-track below exhibits 
only a very faint growth, whilst on the surface there is a liquefied depression with a 
lemon-yellow deposit. Liquefaction proceeds slowly, the track of the needle below 
the surface remaining very faint. 
Agar-agar. —Produces a strong, almost uniform, shining surface-growth of a 
greenish-yellow colour. 
Broth.-— After nine days (August 7 —16, 1886) the liquid exhibits a fine turbidity : 
there is no pellicle on the surface, but a dirty-yellow deposit on the bottom. 
Appearance on plate-cultivation. —On the third day (October 29—November 1, 
1886) the colonies appear as greenish shining expansions, rapidly extending on the 
surface, but remaining small in the depth of the gelatine. 
Under a low power (X 100) the larger surface-colonies exhibit very fine granula¬ 
tion, with a thin smooth edge. The smaller colonies have also a smooth sharp edge, 
with a cloudy interior. (See Plate 17, No. 7a.) 
6. Bacillus Polymorphus. 
Occurrence. —This was obtained as a small colourless pin-head with radiated rim 
on the surface of a gelatine dish which had been exposed to the air on the roof of the 
Science Schools, South Kensington Museum. 
Microscopic appearance. —This organism exhibits a great variety of forms, even in 
cultivations only one day old. In the first place there are seen small fat bacilli, 
almost like micrococci; then there are longer or more oval individuals, frequently 
occurring in pairs, and also forming strings of irregular thickness. In these strings 
there is frequently no division visible, and such an irregular band sometimes reaches 
17p in length. The isolated bacilli are ‘8/x in length and nearly as wide, whilst 
when united in chains they appear several times this size. 
At first sight this variety of form has the appearance of an Impure cultivation. We 
have, however, found the same variety in examining the contents of single colonies 
from plate-cultivations of this organism (see Plate 17, fig. 6, Nos. 66, 6c), and there 
can, therefore, be no doubt that all these forms belong to one and the same 
organism. No. 66 was taken from a colony obtained on plate-cultivation, and No. 6c 
from an agar-tube cultivation. Yiewed in drop-cultivations, they appear almost like 
micrococci, singly and in chains of varying length. Vibratory motion only was 
observable. 
Appearance in Cultivations. 
Gelatine. —Slowly forms a surface-growth which is characterised by the regularity 
of its shape and the minutely serrated nature of its contour. The surface of the 
growth is smooth and white, but in old cultivations the centre becomes tinted slightly 
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