112 



MISCELLANEOUS. 



PT. IT. 



whereas tlie upper part of the stem that had been so 

 suspended in the air by its branches, had gained three 

 inches in circumference.' Bravo ! This is a famous 

 fact for that numerous class of physiologists who, with 

 Priestley and Liebig at their head, believe that trees 

 elaborate their thick bulk from the thin air through 

 the medium of their leaves. And it is a knock-me- 

 down blow to those more commonplace grovellers who, 

 with myself in their rear, fancy that roots may be neces- 

 sary for the growth of timber. But I think that Mr. 

 Wallis must have been mistaken. The effect he de- 

 scribes is precisely w^hat we should expect if the stem 

 were sawed quite rounds but not quite through. Then 

 the thorn would be in precisely the same situation as 

 the barked horse-chestnut which I have just described. 

 The sap would flow from the roots up that part of the 

 heart-wood which was not sawed through, and in its 

 descent through the bark would deposit new growth as 

 low as the w^ound, but no lower. Below the wound 

 no growth would occur ; and the roots, unless the 

 stem broke out below, being unfed, would, in the 

 course of years, die. If this is not the true solution, if 

 the fact stated by Mr. Wallis is a fact, then let us see it 

 again. Nothing can be more easy than to repeat the 

 experiment. Let those who, with Mr. Wallis and the 

 great Liebig, consider the root as a mere pedestal for 

 the mechanical support of the tree and not for the sup- 

 ply of its food, let them try this experiment on their 

 wall-fruit trees. These trees are already nicely ' sus- 



