THE MAPLE. 81 



than merely puncturing the parts to force a liquor to 

 exude ; a simple wound will not accomplish the desired 

 object, as the sap not only hardens on the surface, but 

 acquires a particular form and consistence, and even at 

 times enlarges to a separate vegetable matter. The 

 insect that wounds the leaf of the oak, and occasions 

 the formation of the gall-nut, and those which are like- 

 wise the cause of the apple rising on the sprays of the 

 same tree, and those flower=iike leaves on the buds 

 have performed very different operations, either by the 

 instrument that inflicted the wound, or by the injection 

 of some fluid to influence the action of the parts. That 

 extraordinary hairy excrescence on the wild rose (cynips 

 rosae), likewise the result of an insect's wounds, resem- 

 bles no other nidus required for such creatures that we 

 know of; and these red spines on the leaf of the maple 

 are different again from others. It is useless to inquire 

 into causes of which we probably can obtain no certain 

 result, but, judging by the effects produced by different 

 agents, we must conclude, that, as particular birds re- 

 quire and fabricate from age to age very different re- 

 ceptacles for their young, and make choice of dissimilar 

 materials, though each species has the same instruments 

 to effect it, where, generally speaking, no sufficient 

 reasons for such variety of forms and texture is obvious, 

 so it is fitting that insects should be furnished with a 

 variety of powers and means to accomplish their re- 

 quirements, having wants more urgent, their nests be- 

 ing at times to be so constructed as to resist the in- 

 fluence of seasons, to contain the. young for much 

 longer periods, even occasionally to furnish a supply 

 of food, or be a storehouse to afford it when wanted by 

 the infant brood. 



The wild clematis, or traveller's-joy (clematis vitalba), 

 thrives greatly in some of the dry stony parts of our 

 parish, insinuating its roots into the clefts and passages 

 of our limestone rocks, where those of many other 

 plants could not find admission or support ; and forms 

 in our hedge-rows a heavy shapeless, mass of runners 

 and branches, encumbering and overpowering its neigh- 

 bors ; many of which it often destroys ; and we see the 



