238 STATE OF THE SAP IN WINTER. 



iuffered (o remain twenty hours, as in the preceding experi- 

 ments : and I then found that in Come inftances the wood from 

 the lower, and in the others that from the upper parts of the 

 poles, had given to the water thedeepefl colour and greateft de- 

 gree of fpecific gravity ; but that all had afforded much extrac- 

 tive matter, though in every inftance the quantity yielded was 

 much lefs than I had, in all cafes, found in iimilar infufions of 

 winter-felled wood. 

 Hence many It appears, therefore, that the refervoir of matter depofi ted 



trees have a fuc- j n t ] )e a |b unnim is not wholly exhau (led in the fucceeding: 

 celfion of leaves r . , #. ■ # # , r 



*nd buds. ipping: and hence we are able to account tor the ieveral iuc- 



cellions of leaves and buds which trees are capable of producing 

 when thofe previoufly protruded have been deftroyed by 

 infects, or other caufes ; and for the extremely luxuriant (hoots, 

 which often fpring from the trunks of trees, whofe branches 

 have been long in a ftate of decay. 

 The matter in ^ ^ ave a ^° ^ ome W&HW to believe thai the matter depofi ted 

 the alburnum in the alburnum remains unemployed in fome cafes during 

 imy remain in- f evera i f ucce ffive years: it does not appear probable that it 

 -years. can be all employed by trees which, after having been tranf- 



planted, produce very few leaves, or by thofe which produce 

 neither blolToms nor fruit. In making experiments in 1802, 

 to afcertain the manner in which the buds of trees are repro- 

 duced, I cut off in the winter ail the branches of a very large 

 old pear tree, at a fmall diftance from the trunk ; and I pared 

 off, at the fame time, the whole of the lifelefs external bark. 

 Inftance : in an The age of this tree, I have good reafon to believe, fomewhat 

 •i pear tree, exceeded two centuries: its extremities were generally dead; 

 and it afforded few leaves, and no fruit; and I had long ex- 

 - peeled every fucceflive year to terminate its exigence. After 

 being deprived of its external bark, and of all its buds, no 

 marks of vegetation appeared in the fucceeding fpring, or 

 early part of the fummer; but in the beginning of July nu- 

 merous buds penetrated through the bark in every part, many 

 leaves of large fize every where appeared, and in the autumn 

 every part was covered with very vigorous (hoots, exceeding, 

 in the aggregate, two feet in length. The number of leaves 

 which, in this cafe, fprang at once from the trunk and 

 branches appeared to me greatly to exceed the whole of thofe 

 which the tree had.born in the three preceding feafons ; and I 



5 cannot 



