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) 



