118 College of Forestry 
dark blue coloration taken on by the starch grains contained 
in these cells. In the areas of the growth ring occupied by 
large groups of thick-walled wood fibers both the secondary 
and tertiary lamellee of these elements exhibited a light vio- 
laceous coloration. In sections treated with phloroglucin- 
HCl the walls of the large vessels and the multiseriate pith- 
ray cells are stained most strongly, becoming reddish violet. 
The middle lamell of all the cells also exhibit about the 
same degree of coloration; this is especially striking at the 
cell corners where the middle lamellze often are thickened. 
The remaining layers of the small vessels, the cells of the 
- uniseriate pith-rays, and the tracheids also become colored 
reddish-violet, but the coloration is much less intense than 
that exhibited by the walls of the large vessels. The sec- 
ondary and tertiary layers of the wood fibers: are colored 
still lighter, in fact, almost violet. The elements immedi- 
ately surrounding the large vessels in the early wood of the 
growth ring frequently are colored almost as deeply as the 
vessel walls. After treatment with aniline sulphate-H.SO, 
the walls of the large vessels and the multiseriate pith-rays 
take on a rich golden-yellow. The middle lamellze of all the 
cells also are colored to the same extent and the coloration 
is especially striking at the cell corners. The remaining 
layers of the small vessels, the cells of the uniseriate pith- 
rays, and the tracheids also become strongly yellow-colored, 
, but not nearly so much as the walls of the large vessels. The 
” secondary and tertiary layers of the wood Alene turn only to 
a very pale yellow. The elements immediately surrounding 
the large vessels are colored almost as deeply as the vessel 
walls. 
From the above tests described in full detail, and from 
still other tests employed for the differentiation of both cellu- 
lose and lignin, it is evident that the vessel walls and the 
cells of the multiseriate pith-rays are the most strongly ligni- 
fied elements of the wood. Of the individual elements the 
middle lamellz is the most strongly lignified layer. It is 
clear that the secondary and tertiary layers of the wood fibers 
are the least lignified portions of the wood. As a result of 
