DISEASES OF TAXODIUM AND LIBOCEDRUS. 71 
(fig. 1). The shrinkage of the wall causes breaks to ap- 
pear in the pits (Pl. 5, fig. 11) and after a time in 
the walls (e). The shrinkage in a large mass of wood 
after a time becomes so great that the wood breaks at some 
point and gives rise to the appearance to be noted in 
the long hole at the left of the block in Plate 2. The 
three lamellae of the wood-cell are distinct even in greatly 
‘«charred’’ wood (PI. 4, fig. 2). 
The chemical nature of the wood cells has been entirely 
changed, and, as has been said, the change from sound 
wood to completely charred wood is immediate so far as 
microchemical tests can show. With dilute KOH the dis- 
eased wood swells to two or three times its size and the 
breaks in the walls close. A large per cent. is soluble 
in KOH and from such a solution humus compounds similar 
to those found in the cypress are obtained. Chlor-iodide 
of zinc turns the walls brown. When treated with dilute 
nitric acid the secondary lamellae gradually dissolve and 
there is left a skeleton framework composed of the primary 
lamella, the intercellular substance at the angle, and the 
fine membrane of the pits with the thickened torus. The 
solution takes place very gradually and can be followed very 
readily in a thin section. The nitric acid evidently dissolves 
out the substances into which the secondary lamella has 
been changed, leaving the more resistant primary lamella 
intact. From the HNOs solution a heavy flocculent orange 
mass is precipitated when excess of water is added. This 
precipitate is very soluble in alcohol and acetic acid, 
slightly so in ammonia, insoluble in ether, chloroform, ben- 
zine or acids. When dissolved in absolute alcohol, and 
cooled, no crystals form, but an oily substance settles on 
the walls of the dish as the alcohol evaporates. No further 
attempt was made to determine what this is. Nitric acid 
and potassium chlorate dissolve the entire wood substance. 
With HeSO4 the walls turn black and swell considerably. 
Phloroglucin and hydrochloric acid stain the rotted wood 
49 
