54 
T. TADOKOßO. 
xylan, and araban, the former apparently predominating in amount over the 
latter. 
4. Summary. 
The results of chemical investigations will here be summarized. 
1 . The loss of the stem in water retting as practiced commonly in Hokkai- 
do is about 18 — 19_% but when the retting water is not changed, the loss will be 
14 — 15%. The loss in the stem proper is about 4% less than the amount above 
stated. About 50 — 50% of the total loss is induced by the extractive power 
of the retting water which is naturally influenced by the frequency of 
change. 
2. Nearly all of the constituents of the stem suffer change in the retting 
process but those which are most affected are pentosan (gummy substance) 
and fiber in the bark portion. 
3. The gummy substance in the bark portion of the stem is made up 
largely of xylan and araban, with a small quantity of methyl pentosan. 
IV. General Conclusion. 
The principal results of our investigation hitherto described are here 
summai’ized. 
1. Cutin is the essential constituent of cuticle, aud tannin is found in 
the epidermal cell. Fiber consists of cellulose with a small quantity of 
pectin compounds, protein and fat-like substance as its integral part. On 
the other hand, the cell-wall of cambium, epidermis and parenchyma are 
made up principally of pectin compounds with a small quantity of cellulose. 
The middle lamella of fibers is composed mainly of pectin compounds. 
Lignin forms the chief constituent of the cell-wall of xylem, while pectin com- 
pound forms that of the pith. 
2. Water retting involves anatomical as well as chemical changes of 
