204 THE EVOLUTION OF LIFE 

surprise, the flakes were here composed of beautiful 
well-developed tufts of Mould (Fig. 10, a, a), which 
were growing over and more or less concealing the 
original Bacillus-tufts with Torula corpuscles (6). 
Another of these tubes was then examined, and 
its contents were found to be altogether similar. 
The vessels were made of combustion-tubing, 
and having been sealed when cold, the ends were 
very strong and were thoroughly sound.1 
Superheated hay-infusion, when it ferments, 
invariably retains its characteristic odour, whether 
it has been heated in its natural acid state,? or when 
neutralised, or made slightly alkaline by potash. In 
the process of fermentation an acid of some kind 1s 
generated, since even the slightly alkaline fluid may 
be found distinctly acid when we come to examine 
its contents microscopically. With regard to the 
organisms which are to be found in these fermenting 
hay-infusions, I have occasionally encountered, in 
addition to Bacilli of all lengths and Torule of 
various kinds, Diplococci, and Streptococci in the 
form of short chaplets (Fig. 9, 4). In the fluids 
previously referred to in which the Torule had 
developed into well-grown mycelia, I also met with 
a few organisms (Fig. 9, *) which seemed exactly to 
correspond with Vzdrio Rugula of Cohn. These I 
have never seen in such fluids on other occasions. 
1 The supervention of a more vigorous fermentation, as shown by 
the turbidity, made the fluid more acid ; and this change in the medium 
seems to have brought about the development of the previously existing 
Torula corpuscles. 
2 The acidity is always low, mostly equivalent to I-2 minims of 
liquor potassz per ounce. 
