PUTEEFACTION AND INFECTION. 113 



maintained this colour to the end. On the evening of 

 the 27th every tube of the hundred was smitten, the 

 majority with uniform turbidity, some, however, with 

 mould above and slime below, the intermediate liquid 

 being clear. The whole process bore a striking resem- 

 blance to the propagation of a plague among a popula- 

 tion, the attacks being successive and of different 



Flo. 8. 26th Oct., 7 P.M. 



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>4; 



Mould. Muddy. Cloudy. 



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Slime. Slime and Mould. Clear. 



degrees of virulence. I annex copies of the fourth and 

 seventh maps (figs. 9, 10) with their respective dates. 



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 



