THE planter's GUIDE. 



81 



possessed the stoutest stems, if accompanied with branches 

 and spray pretty thickly set. In the second rank only 

 came the plants from woody glades, of which the roots 

 were so promising, and seemed to confer on them so great 

 a superiority. In other words, it appeared to me that 

 the success of the trees, their new situation and soil being 

 equal, was in the ratio of tlieii^ previous exposure, and 

 their consequent power of protecting the sap-vessels, which 

 power seemed always commensurate to exposure. 



Subsequently various other experiments on a small 

 scale were instituted, with such subjects as could be pro- 

 cured. But in searching for these I was necessarily 

 confined to old and established plantations, which, 

 although of some extent, and containing some variety of 

 soil and climate, were yet imperfectly suited to the 

 purpose. The important transplanting nurseries which I 

 afterwards formed, and which shall be treated of in the 

 sequel, had at this period no existence, and the manifold 

 advantages since derived from them were not then con- 

 templated. Still, a sufficient variety of plants, both in 

 form and species, was obtained, so as to enlarge expe- 

 rience, and render the steps of its progress more interest- 

 ing, and its results more satisfactory. 



In tnese circumstances I was naturally incited to 

 inquire into the causes of such unexpected phenomena, to 

 engage in the study of the anatomy of trees, and of 

 vegetable physiology, or the doctrine of the constitution 

 and properties of plants. And in respect to trees, it is 

 remarkable that little or nothing was known of this 

 science in Europe until the close of the seventeenth 

 century, when the first probable theory of the circulation 

 of the sap was discovered. Indeed, it is only within the 

 last forty or fifty years that the science has been greatly 

 cultivated in Britain ; a,nd it will be admitted as a 



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