112 THE FLOATING-MATTER OF THE AIR. 



remained clear, with here and there a speck of mould on 

 the surface. Of the beef, six were cloudy and one thickly 

 muddy, while spots of mould had formed on the majority 

 of the remaining tubes. Fifteen hours subsequent to this 

 observation, viz. on the morning of the 27th of October, 

 all the tubes containing hay-infusion were smitten, 

 thoug'h in different degrees, some of them being much 



Fig. 7. 2Gth Oct., noon. 



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Clear. Mould. Cloudy. Muddy. 



more turbid than others. Of the turnip-tubes, three 

 only remained unsmitten, and two of these had mould 

 upon their surfaces. Only one of the thirty-five beef- 

 infusions remained intact. A change of occupancy, 

 moreover, had occurred in the tube which first gave 

 way. Its muddiness remained grey for a day and a 

 half, then it changed to bright yellow-green, and 



