Fischer . — The Biology of A r miliaria mucida , Schrader. 531 
stain colours the walls that are still lignified a light pink, with the middle 
lamellae standing out a darker shade, and the secondary layers remain 
uncoloured or stain green. The hyphae are stained olive green. 
With safranin and Hoffmann’s blue the host tissues are pink and 
the hyphae blue. 
The hyphae may pass from cell to cell through the pits, but also bore 
their own way through the intact walls. The diameter of the hyphae varies 
considerably, ranging from 2 to 5 fx. 
Pieces of a diseased branch that actually bore carpophores of A. mucida , 
and the wood of which was in an advanced stage of decay, were ground up 
into a powder, which was left to soak in 50 per cent, glycerine for about 
five weeks. In the filtrate obtained from this, small pieces of sound beech 
wood were immersed for 2 \ months. No structural change was visible, but 
treated with Schultz’s solution, though the starch was found to be practically 
intact, there were distinct signs of delignification of the secondary layers of 
the cell-walls, which were stained a more or less deep violet to pale lilac, 
according to the degree of decomposition, with the middle lamellae yellow. 
In places, too, the secondary layers were detached from the middle lamellae 
and contorted, much as was the case in the diseased wood described above, 
though not to the same extent. 
I feel justified, therefore, in concluding that the fungus secretes an 
enzyme, or enzymes, capable of reducing the starch and of reconverting the 
xylem to cellulose. 
III. Remedial and Protective Measures. 
Whatever the eventual conclusions as to the parasitic nature of 
A. mucida may be, it is certain that it causes serious detriment to beech 
timber, rendering it unfit for anything but fuel of a poor quality. It is 
possible that it is not a parasite at all, but it is none the less a foe of the 
beech forest and, like some other xylophile fungi, may require a preparation 
of the tissues by other organisms or by special conditions before it can avail 
itself of the nutriment they afford. Therefore, it is advisable to consider 
what precautions can be adopted to prevent its gaining an entrance into 
beech trees, and what can be done to eradicate it once it has established 
a footing. 
The taking of active steps against fungoid diseases must ever be 
controlled by the question of cost. In maladies such as the one under con- 
sideration it too often happens that the necessary expenditure is out of 
proportion to the benefit to accrue. Nevertheless, it will be readily con- 
ceived that where beech is grown commercially this fungus, given suitable 
conditions, might inflict such losses that heavy expenditure on its eradica- 
tion, and in subsequently protecting the forest against its inroads, would be 
O o 
