CHAP. XL] AN EPISODE. 351 



winians will take any interest), I proceed to notice what 

 Mr. Wright exhibits as a good illustration of the An illustra . 

 origin of species by Natural Selection in the shape g^tVofa 

 of the growth of a tree. It is so, he tells us : 



&quot; For its branches are selected growths, or few out of many thousands 

 that have begun in buds ; and this rigorous selection has been effected 

 by the accidents that have determined superior relations in surviving 

 growths to their supplies of nutriment in the trunk, and in exposure 

 to light and air. This exposure (as great as is consistent with secure 

 connection with the sources of sap) seems actually to be sought, and 

 the form of the tree to be the result of some foresight in it. But the 

 real seeking process is budding, and the geometrical regularity of the 

 production of buds on twigs has little or nothing to do with the 

 ultimate selected results, the distributions of the branches, which are 

 different for each individual tree. 



&quot; Now, I willingly accept this illustration, which I propose 

 to turn round and make use of against its author s view, and 

 for the purpose of showing that it exemplifies, not the origin 

 of species by Natural Selection, but the origin of species by 

 innate law, modified by the subordinate action of Natural 

 Selection. 



&quot; For, in fact, does not every one know that, in spite of these 

 external influences, each kind of tree has a certain general 

 character of growth which is definite and unmistakable. The 

 oak, the fir, the birch, &c., each has its own special fades. 

 Mr. Wright does not deny this ; he says : 



&quot; The general resemblance of trees of a given kind depends on no 

 formative principle other than physical and physiological properties in 

 the woody tissue, and is related chiefly to the tenacity, flexibility, and 

 vascularity of this tissue, the degrees of which might almost be inferred 

 from the general form of the tree. 



&quot; Precisely so. But on what do these physical and physio 

 logical properties depend? It is useless to endeavour to 

 avoid the admission ; we shall always be compelled by reason 

 to confess the existence, in each seed, of a principle, an 

 intimius principium conditioning the evolution of the plant 

 according to its nature and laws. To deny that there is 

 a something giving unity to the composite whole, and unity 



