ATMOSPHERE IN RELATION TO PUTREFACTION AND INFECTION. 
65 
On the 31st of October I finally inspected the tray of tubes. All those containing the 
hay-infusion were turbid, some thicker and much more deeply coloured than others. 
They were all at first alike in colour. Out of the thirty tubes four only were free from 
Map IV. 27th Oct., 6.30 p.m. 
Map VII. 29th Oct., 10.30 a.m. 
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Muddy. 
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Cloudy. 
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Muddiness 
subsided as slime. 
Slime. Slime and mould. Clear. 
mould. Three of these were adjacent to each other, the fourth at a distant portion of 
the tray. 
The Penicillium was exquisitely beautiful. Its prevalent form was a circular patch 
made up of alternate zones of light and deep green. In some cases the liquid was 
covered by a single large patch ; in others there were three or four patches, each made 
up of its differently coloured zones. Reticulated patterns also occurred. Three kinds 
of Penicillium seemed struggling for existence, namely : — that just described ; a second 
kind, of the same consistency and colour, but forming little rounded heaps instead of 
circles ; thirdly, a woolly, voluminous, white mould, in the middle of which a zoned circle 
of the other mould sometimes formed a little islet. 
All the tubes containing the turnip-infusion were also turbid on the 31st. Nine of 
them were free from mould. This, where it occurred, exactly resembled small cocoons in 
shape. The beef-tubes were also all turbid on the 31st, and seventeen of them were free 
from mould. The mould upon the beef, moreover, was much less luxuriant than that on 
the hay- and turnip-infusions. The mould-developing power is obviously greatest in the 
hay-, less in the turnip-, and least of all in the beef-infusion. In every case where the 
mould was thick and coherent the Bacteria died, or became dormant, and fell to the 
