82 MICRO-ORGANISMS FROM THE BRISBANE AIR. 



the surface of gelatine show a wider streak than the preceding, 

 and stab cultures spread more widely at the surface. Lique- 

 faction occurs tardily after the first week. It is a moderately 

 stout bacillus, occurring in roundish, oval, and short rod-like 

 forms, but does not appear to form long rods and is non- 

 motile. 



Bacillus K is a moderate-sized, fairly stout bacillus, very 

 similar to the preceding in morphological characters, but some- 

 what larger. It has no power of movement. Growths on agar 

 develop rapidly, are whitish, with a faint yellowish tinge, which 

 is better developed on potato cultures. Grown in gelatine it 

 ■causes rapid liquefaction. 



Bacillus TT is a large, stout bacillus with rounded ends, very 

 variable in length, but never forms long filaments. In young 

 cultures many individuals show well marked, but sluggish, 

 independent movements. Like all the preceding it does not 

 appear to form spores. Its growth on agar is white, the centre 

 of the various colonies being opaque, the periphery thin and 

 transparent. It has a very feeble power of liquefying gelatine 

 in old cultures. A stab culture develops slightly along the 

 track of the needle, and spreads for a moderate distance at the 

 point of entry. Occasionally feathery whorls spread out from 

 the upper part of the stab into the substance of the jelly. 



Bacillus o- is a very interesting organism. Its growths on 

 .agar spread at the edge in looped skeins of filaments, closely 

 resembling the well-known growths of Bac. suhtiUs. If an old 

 ■colony is examined, it will be found to consist at the edge of 

 these filaments, which readily break up into rods, but the 

 <;entral portions consist almost entirely of a mass of spores. 

 Its growth on gelatine at once differentiates it from Bac. .suhtuin. 

 There is a slight growth along the track of the needle. From 

 the point of entrance, a fine feathery growth spreads all over 

 the surface, and the gelatine never liquefies. On a gelatine 

 plate. the colonies develop much more slowly than those of Bac. 

 jiubtilis, the early stage of which they resemble, but differ in the 

 entire absence of the circular liquefaction and rapid growth 

 . ■characteristic of the latter. On potato, bacillus o- develops 

 slowly and scantily. The best method of observing its growth 

 and spore formation is in a hanging drop of bouillon. When 



