THE BEGINNJNGS OF LIFE. 55 



taking place within living beings, are capable of being 

 built up artificially by the chemist in his laboratory ; 

 and if it can be shown that the shapes and forms 

 assumed by such organic structures are the natural 

 resultants of incident forces acting upon the plastic 

 and modifiable tissues of which they are composed 

 then may we indeed say that much of the mystery 

 which formerly obscured vital phenomena is being 

 gradually removed. But let it not be supposed that 

 we go further than this, that we suppose all mystery 

 has vanished. No, enough still remains to fill our 

 minds with the deepest awe and reverence. The 

 most intimate processes and phenomena of Life 

 remain utterly inexplicable. We have removed the 

 thick husks, but the kernel of the nut as yet lies 

 hidden, enveloped in an impenetrable shell. What 

 do we know concerning the actual phenomena of nutri- 

 tion? They are still inscrutable mysteries. By what 

 molecular or other laws does an organic unit assi- 

 milate to itself matter of a particular kind out of a 

 complex mixture, convert it into its own substance, 

 and endow it with its own properties of doing like- 

 wise? Believing, as we may, that sensation and thought 

 are the products of molecular changes taking place in 

 nerve organs, does this belief assist us one iota in 

 explaining the deeper facts ? Can we at present frame 

 to ourselves any possible or conceivable way in which 

 mere molecular motion can result in the manifestation 

 of such phenomena as sensations, thoughts, and all the 



