110 THE ESSEX NATURALIST.
air in the vessels contracts so that the preservative is sucked into
the wood.
In buildings the use of dry wood and adequate ventilation,
especially of cellars and such like places, will go far to prevent
the depredations of dry rot fungi. In repairing damage which
has already been done the removal of all infected and con-
taminated wood and its immediate burning is the first requisite.
Since some of these fungi can creep over or through brickwork
and stone, such must be gone over thoroughly with a flame, and
woodwork washed down with formalin or some similar toxic
substance, to kill spores and mycelium. Treatment of the new
wood with a suitable preservative is also desirable ; all wood
shavings and chips should be removed and burnt, and if there be
an earth floor this might also, with advantage, be sterilised by
the use of quicklime or some antiseptic, since the fungus may be
present in the soil.
From what has been said of preventive measures it will be
apparent that in designing suitable preventive or remedial
measures against wood-destroying fungi the first requisite is a
thorough knowledge of the life-history and mode of life of the
attacking fungus. Armed with such a knowledge it may be
possible to find some weak point at which the fungus can be
attacked. Fresh wood may be invaded by means of mycelium
or spores, and, thanks to the amazing prolifieness of fungi, spores
are everywhere present, and it is not long before any suitable
substratum is colonised. To prevent the appearance of such
substrata, or effectively to render them untenable with the
least possible delay, is the basis of our methods ; once the fungus
has. established itself in the tree or timber, a cure, even if one be
known, is less practicable. Such a course, together with a
rigorous use of fire whenever possible, at least serves to keep the
organisms in check.
The Identification of Wood Rots. Reference to any
fungus flora will show that descriptions of genera and species are
almost entirely descriptions of fruit-bodies of fungi, and given
typical fruit-bodies the botanist is able, with sufficient practice,
to put a name to the fungus which produced them. Fungal
hyphae, however, are so similar to one another that they would
not serve for purposes of taxonomy, although they are occasion-
ally, as we have seen, characteristic in certain species. Similarly,