338 TEAXSACTIOXS AND PEOCEEDIXGS OF THE [Sess. lix. 



upon, but continued to live below that part. The laburnum, 

 however, was killed outright. 



The results of these experiments point to the following 

 conclusions : — 



1st. In those species which form no true heart- wood, the 

 water ascends freely through the central portion of 

 the stem as well as through the outer portion. 



2nd. In those species which form a true heart-wood 

 (duramen), the ascent of the water is confined to 

 the region of the sapwood (alburnum). 



The results are the outcome of one year's observation 

 only, but the subsequent fate of the trees will be recorded. 



The following appearances were produced during the 

 succeeding summer on the stems at the parts which had 

 been operated upon : — 



Horse-chestnuts (^sculus Hiiopocastanum, Linn.). — 

 Where the bark only had been removed, a callus was 

 formed at the cut edge of the cambium both above and 

 below, and from the under one a thick crop of shoots 

 was produced. Where both bark and wood had been 

 removed, a callus was formed both above and below, but 

 from the under one a few shoots only were produced. 



Maples {Acer Pseudo-Platanv.s, Linn.). — "\Miere the bark 

 only had been removed, a callus was formed above, but 

 none was formed below. Where both bark and wood had 

 been removed, a callus was formed both above and below, 

 and a few shoots were produced from the under one. 



Beeches {Fagus sylvatica, Linn.). — "Where the bark only 

 had been removed, a callus was formed both above and 

 below (principally above), but no shoots were produced. 

 Where both bark and wood had been removed, a slight 

 callus was formed below, but none was formed above. Xo 

 shoots were produced. 



Oaks {Qucrcus Cerris, Linn., and Q. Robur, Linn.). — In 

 the Turkey oak, from which the bark only had been 

 removed, a callus was formed both above and below, but 

 no shoots were produced. (It may be interesting to note 

 that in this case small isolated patches of phloem, which 

 had been left adhering to the stem in the operation of 

 barking, developed a well-marked callus all round their 

 edges. The supplies of nourishment which these received 



