125 
Xylem of Woody Stems 
wood fibres in certain small sections might give no cellulose reaction, on 
taking complete transverse sections I never failed to detect this reaction 
in some area or another. 
When stems of a larger diameter were employed it became necessary 
to divide them into smaller areas, and for this purpose they were cut into 
blocks about 1.3 cm. square. These blocks were numbered, and by this 
means a transverse section of a large stem was obtained. In one instance 
the base of a young branch approximately sixteen years old, measuring 
5.4 by 3.8 cm., was divided by a fine saw into twelve blocks ; sections were 
cut from each of the blocks, stained with Delafield’s haematoxylin and 
mounted in Canada balsam. Although not one of these block-sections 
could be found which did not contain some fibres with a broad violet inner 
lining, in some they were quite isolated, while in others (more especially 
on the lower side) they presented a very conspicuous feature, so much so 
that their presence could be distinctly discerned by the unaided eye. 
In another instance I specially felled a young Oak, approximately 
forty years old, the stem measuring 14 cm. by 12 cm. This was divided 
by a fine saw into eighty-eight blocks, all of which were numbered in 
order, and transverse sections were cut from each, stained in haematoxylin 
and mounted in Canada balsam. In this way a complete transverse section 
of this trunk was obtained. As in the case of the smaller branch some 
fibres with a violet lining could be detected in almost every one of the 
eighty-eight sections, but in certain portions of the stem they occurred 
in very conspicuous groups. These fibres were well marked in the blocks 
situated in the centre of the stem, that is around the pith, and containing 
the first few years of growth, which showed that the oldest wood was not 
completely lignified and contained a large proportion of cellulose. Its 
presence in the wood of the first years of growth was also noticed in many 
smaller stems. The cellulose was somewhat irregularly distributed, though 
it was evidently developed more markedly on one side of the tree than 
the other, and it is probable that the orientation has some influence in 
this direction (Fig. 1). 
The trees above-mentioned were growing in the neighbourhood of 
Newcastle-upon-Tyne. It became an interesting question to determine 
whether climatic conditions had any influence upon the composition of 
the xylem, and specimens of Oak were obtained from other parts of 
England, i. e. from Warwickshire, Yorkshire, and Surrey. Transverse 
sections from Oaks growing in all these localities presented the same 
appearance, when stained with haematoxylin, as has been already de- 
scribed. Fig. 2 represents a section of an Oak from Wimbledon, taken 
from a branch eight years old, diameter 1.3 cm., showing strikingly the 
inner cellulose layer of the fibre-walls. The cellulose extended about 
one-third round the stem. From Warwickshire I was fortunate in obtaining, 
