ON SOME NEW MICRO-ORGANISMS OBTAINED FROM AIR. 
265 
Microscopic appearance. —Under a high power ( X 1 ,000) this is seen to be a small 
micrococcus, varying in size from ’5/x to '8/x, the dimensions being thus fairly uniform. 
The cocci are arranged in short chains, as seen in Plate 18, fig. 3, No. 3a. 
Appearance in Cultivations. 
Gelatine. —After four days (August 6—10, 1886) the needle-track below the 
surface is very faint; at the top there is a slight depression, with a light lemon-yellow 
deposit, slight liquefaction of the gelatine having there taken place. As the cultiva¬ 
tion becomes older, the liquefaction slowly proceeds, the needle-track in the still 
solid gelatine remaining very faint. 
Agar-agar. —Forms an almost colourless shining growth extending even after a 
month, but slightly to left and right of needle-streak. 
Broth.- —After nine days (August 7—16, 1886) the liquid is clear, free from pellicle, 
and has a dirty yellowish-white deposit. 
Appearance on plate-cultivation. —To the naked eye the colonies appear as 
yellowish pin-heads on the surface, each being surrounded by a slight depression. 
Under a low power (x 100) the smaller colonies appear irregularly circular (see 
Plate 18, No. 35), the edge is smooth, and the interior is more or less granular. 
In gelatine the growth of this organism presents points of similarity to that of 
Sarcina lutea, from which, however, it is most sharply distinguishable, not only by 
its appearance under the microscope, but also by its growth in agar-agar. 
4. Sarcina Lutea. 
Occurrence. —We have not ourselves found this organism in the air, but a cultiva¬ 
tion of the same was brought by one of us from Dr. Koch’s laboratory at the 
Hygienic Institute of Berlin. 
It has already been partially described by Klein (‘ Micro-organisms and Disease,’ 
1885, p. 43), Eisenberg (‘ Bakteriologische Diagnostik,’ 1886), Crookshank 
(‘Introduction to Practical Bacteriology,’ 1886, p. 120), Flugge (‘Die Mikro- 
Organismen/ 1886, p. 179). 
Microscopic appearance. —Under a high power ( X 1,000) there are seen large cocci, 
mostly grouped together in cubical packets of four or more. The individual cells vary 
in diameter from l'5p to 2'5/x, and are best seen when lightly stained with methylene- 
blue. The staining is very liable to be too intense and so prevent the grouping 
being recognisable, owing to their lying in heaps, the division of the cells taking place 
both vertically and horizontally. (See Plate 18, fig. 6, No. 65.) 
The appearance in drop-cultures is particularly characteristic, the arrangement in 
cubical packets being most beautifully shown. It is, of course, non-motile. 
Appearance in Cultivations. 
Gelatine. —In the tube it grows slowly, forming numerous minute yellow centres in 
the track of the needle, whilst on the surface it produces a shining lemon-yellow 
2 M 
MDCCCLXXXVII.—B. 
