530 Fischer . — The Biology of A r miliaria mucida , Schrader . 
The tests applied showed that there was an early disappearance of the 
starch, followed by a gradual delignification of the secondary layers of the 
cell-walls of the wood. These layers become swollen and detached from 
the middle lamellae, and, owing to the want of space in the lumina in their 
expanded condition, they are curled up and contorted (Fig. 34). Gradually 
these disorganized tissues decompose and are absorbed by the hyphae, until 
only the middle lamellae are left (Fig. 33). In this state the wood is full of 
air and has become soft and lighter in colour. 
The early stages tested with iodine or chlor-zinc-iodine gave no starch 
reaction. At a later stage with phloroglucin results similar to those ob- 
tained by Marshall Ward in the case of Stereum hirsntum (28) presented 
themselves. The middle lamellae stained a deep bright pink, the layers 
next to them were of a lighter pink, and the innermost swollen layers 
remained colourless, showing delignification from the lumen outwards. 
The cells of the medullary rays and of the wood parenchyma retained 
their lignin intact for a longer period, showing up in the advanced stages 
more or less bright pink in the midst of colourless fibres, vessels, and 
tracheids. 
In the advanced stages the secondary layers of the cell-walls before 
their absorption gave a cellulose reaction with chlor-zinc-iodine, demon- 
strating the reduction to cellulose. This was too general and too complete 
to be referred to want of lignification as suggested by Potter (20) ; moreover, 
sound wood similarly tested gave no violet colour. 
Evidence in the same direction was obtained with the gentian violet 
and Congo red stain. The lignified walls took on a blue stain, and those 
converted to cellulose coloured pink with the Congo red. The reactions, 
however, were not so very definite as the results obtained by Biffien. 
With ruthenium red and methyl green the middle lamellae stained 
a cherry red, and the secondary layers either remained colourless, especially 
where much swollen and contorted, or took on a light green tint. 
After the disappearance of the starch, products of decomposition 
of a brown colour are present in the cells of the medullary rays and of the 
parenchyma. Tested with ferrous sulphate they showed no trace of tannin, 
and the alkalin test betrayed no oil. 
In the cubes of beech wood on which the mycelium had grown in pure 
culture, no structural change could be detected after two months, and 
no chemical alteration was revealed by the phloroglucin test. After the 
lapse of five months, however, the secondary walls were affected. With the 
diamant fuchsin and light green stains the structural changes described 
above for advanced stages of attack were verified ; the detachment and 
partial disappearance of the secondary layers being evident. 
The course of the hyphae in the wood can be followed in the sections 
stained with the diamant fuchsin and light green method (Fig. 35). This 
