10 PLANT LIFE 
inorganic worlds now appears less sharply 
defined than formerly, and many reactions 
which used to be regarded as immediately 
and essentially associated with life and active 
vitality are now recognised as being sus- 
ceptible of a less mystical interpretation. 
Thus it has become more and more clearly 
apparent during the last few years how great 
a share the various ferments may take in 
promoting those reactions which formerly 
were regarded as inseparable from the living 
organism. 
Now although these ferments, in the 
narrower sense, are doubtless the products of 
protoplasmic activity, they can initiate and 
carry out their specific reactions in a test- 
tube under conditions which are incom- 
patible with the concurrence of life in the 
ordinary, or indeed in any real, sense of the 
word. Evidence is accumulating to show 
that the ferments owe their specific activities 
to their physical structure, and that they 
approximate to the singular class of “ cata- 
lytic ’ inorganic bodies, which, like them, 
are able to promote and accelerate certain 
chemical changes without themselves under- 
going destruction. 
Indeed, as time goes on, exact investigation 
is continually lifting corners of the curtain 
which conceals the mysteries of life, and the 
glimpses we have caught tend to suggest that 
although the reactions which are going on 
in the living laboratory are (at present) 
