ON SOME NEW MICRO-ORGANISMS OBTAINED FROM AIR. 
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(X 100) the whip-like extensions noticed above had enormously increased, the 
greater number of the colonies having the appearance presented in Plate 20, fig. 3, 
No. 3c ; others, again, like that shown in Plate 20, fig. 3, No. 36 ; and others partaking 
of the character of both these, as shown in Plate 20, fig. 5, No. 5/ After 3G hours 
the colonies had further increased in size, and in many cases the whip-like extensions 
had become much thickened; in some colonies these gave rise to a star-fish appearance, 
which is easily visible to the naked eye. 
We have established beyond doubt that all the above forms of colony are derived 
from one and the same organism, inasmuch as we have repeatedly prepared plates by 
inoculation from single colonies and again obtained colonies of the same diversity in 
appearance. 
11. Bacillus Subtilis. (Hay Bacillus.) 
Although this micro-organism has become classical through the great care with 
which it has been described by numerous authorities, including Cohn, Koch, Klein, 
Flugge, and many others, it is only recently that the appearances to which it gives 
rise on plate-cultivation have been recorded (Eisenberg, loc. cit Flugge, loc. cit.). 
We have had occasion to carefully examine the appearances produced by this organism 
in order to compare them with those resulting from some of the organisms described 
above. For the purposes of this comparison, we have employed a cultivation which 
was obtained by one of us from Dr. Koch’s laboratory in Berlin. 
Microscopic Appearance. 
The single bacilli vary in length from l'7p to 6*8 p, and are about 1‘7/x in 
width ; the ends are slightly rounded, but sometimes nearly rectangular. Prior to 
spore-formation the bacilli become thicker and more square (see Plate 20, fig. 5, No. 5c), 
and, as described in the case of B. cereus , these thicker forms present a very 
different appearance to the ordinary bacilli. The bacilli also grow into threads, which 
are frequently of great length. The spores, which are to be seen in all but the newest 
cultivations, have a length of about 2'5p, and are about lp in width ; they are oval, 
and present, as usual, a bright and shining appearance, which, together with their 
property of not staining with aniline colours, renders them easily distinguishable from 
the bacilli. In Plate 20, fig. 5, Nos. 5c and 5 g, these various forms are represented ; 
thus in No. 5 g are the ordinary bacilli, also the thickened bacilli, also bacilli containing 
spores; whilst in No. 5c a thread is shown composed of numerous segments, also a 
similar thread which has become thickened and exhibits a spore in each segment. 
Viewed in drop-cultivations, the isolated bacilli are seen to be very motile, but 
there are also stationary masses of bacilli which are non-motile. Subsequently 
threads and spore-formation are observable, as previously described in the case of 
B. cereus. 
2 0 
MDCCCLXXXVII.—B. 
