XV, 4 
Oshima: Formosan Termites 
339 
Besides the above-mentioned damage, that done to bridges, 
telegraph poles, books, paper, wood pulp, cotton, and clothing 
is sometimes very serious. 
PRINCIPAL FOOD OF COPTOTERMES FORMOSANUS 
The stem of an exogenous perennial is a complex of struc- 
tural elements of varied form and function. Of these we may 
distinguish three main groups: a, vessels; b, wood cells proper; 
c, medullary tissue. The growing cell of plant tissue consists 
of cell wall and protoplasm, the living functions depending upon 
the activity of the latter. However, the above-named three 
main structural elements of the wood do not contain nitrogenous 
substance — that is, protoplasm — but mainly consist of the special 
constituent of the cell wall known as cellulose. 
There are, as might be expected, a great many varieties of 
cellulose, and the term must be taken as denoting a chemical 
group. Cellulose, taken as a group, presents the following 
characteristic: A colorless substance, insoluble in all simple 
solvents; generally but variously resistant to oxidation and 
hydrolysis; nonnitrogenous, having the empirical constitution 
characteristic of the carbohydrates. The composition of pure 
cellulose is represented by the percentage numbers C 44.2, IT 6.3, 
0 49.5, corresponding to the empirical formula (C 6 H 10 Q 5 ) X . It 
is flexible, slightly elastic, permeable, but only slightly absorbent, 
and does not readily undergo fermentation. 'When treated with 
acid it passes into a starchlike condition, as is evidenced by 
its turning blue with iodine; and under certain conditions in 
the living plant it would seem capable of being formed from 
sugar or of passing into it. 
It must be noted, however, that the typical cellulose is not 
separated from the plant in a pure state, but in admixture or 
in intimate chemical union with other compounds or groups 
of compounds. The latter are distinguished by greater reac- 
tivity; for example, they readily yield to alkaline hydrolysis, to 
oxidation, or to the action of the halogens. In the latter is 
included the very important group of lignified cellulose, or 
lignocellulose, distinguished by the presence of ketohexene groups 
in union with the cellulose, and therefore combining directly 
with the halogens. 
Generally, walls of cellulose, fibers, and vessels in the wood 
acquire mechanical strength or resistance by undergoing a 
change known as lignification. This consists in their impreg- 
nation with a substance known as lisrnin, forming a compound 
