414 Petch.—Mocharas and the Genus Haematomyces. 
This swelling appears to take place in the inner layers, i. e. those bordering 
on the lumen of the cell. At the same time hyaline globules appear on 
the inner surface of the cell-wall and increase in number until in some cases 
they almost fill the cells : frequently these globules form short chains, Gl- 
are united in botryoidal masses. The cells then separate along the middle 
lamella, and intercellular spaces are formed which become filled with slime. 
The loose cells lose their brown colour, and their walls are reduced to 
a thin membrane and collapse. These collapsed cells, embedded in slime, 
completely fill the gallery with a disorganized mass. 
The globules on the cell-walls, or in the cells, at first stain yellow- 
brown with chlor-zinc-iodide. They do not stain with Sudan III. But 
in the older modified cells, they stain black with chlor-zinc-iodide. This 
change appears to take place from the centre of the globule, as many of 
them stain black in the centre, with a yellow-brown translucent margin. 
It thus appears that these starch (or amyloid) bodies are formed from some 
constituent of the cell-wall. The grains observed in the cells of the exuded 
Mocharas are not the residual starch of the cortical parenchyma. On 
staining a section of the abnormal cortical layer with chlor-zinc-iodide, 
it is very noticeable that while innumerable granules in the disorganized 
mass stain black, nothing of the kind occurs in the surrounding unaltered 
parenchyma. There is no starch in the unaltered cells of the abnormal 
cortical layer. 
A similar formation of Mocharas takes place in the old normal cortex 
in small pockets between the fibres, but this occurs only to a small extent, 
and it does not seem to contribute much to the amount exuded. The 
chief source of the exudation is the abnormal layer of cortical parenchyma 
which is developed after the tree is felled. Consequently, Mocharas exudes 
principally along the line of the cambium, or from cracks which extend 
almost completely through the cortex. 
The lignified vessels of the abnormal cortical layer do not form part 
of Mocharas. They are pushed to one side, as the galleries are enlarged 
by the disorganization of the surrounding cells. 
When the mass exudes, the cells expand and assume an oval or 
spherical shape. A few are brown, with brown contents, but the majority 
are hyaline, and contain a cluster of amyloid bodies. No crystals occur in 
the exudation. The red-brown or purple-brown coloration of the outer 
layer appears to be produced not only by exposure to the air, but also by 
a transfer of some colouring matter from the interior outwards. When 
first exuded, Mocharas is pale yellow, or yellowish white, but when the 
outer layer has turned red brown, the interior appears distinctly whiter. 
When a piece of Mocharas, about three or four weeks old, was boiled 
in water, it swelled up and resumed its original shape. At the same time 
its colour changed to yellow, and the water became deep red. When left 
