THEORY AND PRACTICE. 93 



the lifetime of Liebig is one of the happiest and 

 most remarkable. If some great physical event had 

 testified to men's bodily senses the motion of the Earth 

 round the Sun, and the steady centricity of that lu- 

 minary, during the exact lifetime of Copernicus 

 or Galileo ; or if some conceivable reflection of the 

 earth's surface in the deep azure of heaven, had ex- 

 hibited to man's wondering eyes the outline of the 

 great American continent looming along its obverse 

 hemisphere, just as Columbus was collecting sub- 

 scriptions for his first equipment in quest of it, 

 they would not each have furnished a more triumph- 

 ant vindication of the achievements of those master- 

 minds, during their own existence upon earth, than 

 that which the more fortunate Professor of Giessen 

 has been destined to witness. No sooner had the 

 persecuting infidelity of man (the same in every age) 

 begun to crucify his great theory of THE NUTRITION 



OF PLANTS FROM THE ATMOSPHERE, than the US6 of 



Guano and of inorganic manures began to give it 

 proof. "Burn -a plant, whether it be an Oak-tree or 

 a stalk of Clover," (for so the assertion of the great 

 Analyst may be briefly epitomized,) "and the trifling 

 ash it leaves will show you all it ever got from the 

 soil." But the bulk, the weight, the great mass of 

 its vegetable structure where is that gone? 



