i\\Kis. 481 



troduced species G. sinensis seems to stand well, and is 

 likely to attain considerable size. An original specimen of 

 Sophora Japonica *, nearly forty years old, now forms a 

 large tree, perhaps 45 feet in height, with a stem 3 feet in 

 circumference. Robinia viscosa is about 40 feet high ; 

 Quercus pyramidata about 20. 



We were previously acquainted with the clever little 

 treatise of M. Du Petit-Thouars, which bears the quaint 

 title of " Histoire d'un Morceau de Bois ;" and were not 

 surprised, therefore, to perceive on many trees marks of ex- 

 periments on the circulation of the sap, shewing that the 

 bark and the wood can alternately act as its conductor. 

 In several young sycamore-trees (Acer pseudo-platanus), 

 he had, in April or May last^ removed, to the extent of 

 two or three inches, the central wood and pith, leaving the 

 tree to be supported only by four pillars of bark : in others, 

 he had taken off, to a similar extent, the outer bark, liber 

 and alburnum, leaving the trees to be supported solely by 

 the central wood. In both cases, the trees were still living, 

 but not making shoots so vigorous as those which remain- 

 ed untouched. In these instances of experiments on the 

 sycamore, the wounded parts were left fully exposed to the 

 air. Several other kinds of trees had died when so treats 

 ed ; but different species had survived, when plasters were 

 applied, so as to exclude the action of the atmosphere, and 

 form a temporary covered canal for the circulation of 

 the juices. On a Bourdine peach-tree an experiment in 

 ringing was now going on : a particular branch was de- 

 prived of a portion of its bark all around, and the incision 

 appeared to have been carried fully down to the wood ; at 

 the same time means were employed to keep the branch 



* An elegant weeding variety of this tree, hitherto unknown in Scotland; 

 eiists at Asnier, near the Bridge of Ncuilly. 



h h 



