MICEO-OPiGANISMS FEOM THE BRISBANE AIR, 



By A. JEFFERIS TURNER, M.D., Lond. 



[Bead before the Boijal Societt/ of Queensland, Jidij 11, 1S96.] 



During the past eighteen months I have made a series of 

 observations on the bacterial flora of the air of Brisbane, and I 

 propose to give a short account of the results so far obtained, 

 reserving fuller details for a subsequent occasion, when my 

 observations shall have been more complete. 



The method employed was simple. It was not my object 

 to estimate the number of micro-organisms present in the air, 

 but to obtain pure cultures of the different species, and to 

 examine their morphological and cultural differences. The 

 ordinary nutrient agar jelly (2 per cent, agar, 1 per cent, 

 peptone, 0.5 per cent, common salt in beef broth) was poured 

 into a sterilised Petri dish and allowed to cool. The plates so 

 obtained were usually kept covered for a few days in order to 

 allow the superfluous moisture to evaporate, and were then 

 exposed by removing the cover for from two to five minutes. 

 Some of these exposures were made in the laboratory, but th& 

 greater number in a small paddock outside, the dish resting on 

 the top of a six-foot post. These agar-plates I have found 

 preferable to gelatine plates for this purpose, inasmuch as 

 they can be kept longer ; whereas the latter rapidly liquefy, 

 so that slowly-growiug organisms may be lost. Further, on 

 the old plates the colours of the pigment-producing organisms 

 become far better marked than on recent plates. 



The desiccated condition of the organisms deposited from 

 the air is unfavourable to rapid development, and colonies are 

 not visible to the naked eye before the second day. A few 

 barely visible specks then can be usually detected by careful 



