limp much sooner than others. If the
plants get too moist the gills crush together when pressed, and
otherwise they do not make such good specimens. When the specimens are
dried and placed in the herbarium they must be protected from insects.
Some are already infested with insects which the process of drying does
not kill. They must be either poisoned with corrosive sublimate in
alcohol, or fumigated with carbon disulphide, and if the latter it must
be repeated one or two times at an interval of a month to catch those
which were in the egg state the first time. When placed in the herbarium
or in a box for storage, naphtha balls can be placed with them to keep
out insects, but it should be understood that the naphtha balls will not
kill or drive away insects already in the specimens. Where there are
enough duplicates, some specimens preserved in 75 per cent. alcohol,
under the same number, are of value for the study of structural
characters.

CHAPTER XVIII.

SELECTION AND PREPARATION OF MUSHROOMS FOR THE TABLE.

In the selection of mushrooms to eat, great caution should be employed
by those who are not reasonably familiar with the means of determination
of the species, or those who have not an intimate acquaintance with
certain forms. Rarely should the beginner be encouraged to eat them upon
his own determination. It is best at first to consult some one who
knows, or to send first specimens away for determination, though in many
cases a careful comparison of the plant with the figures and
descriptions given in this book will enable a novice to recognize it. In
taking up a species for the first time it would be well to experiment
cautiously.

=No Certain Rule to Distinguish the Poisonous from the Edible.=--There
is no certain test, like the "silver spoon test," which will enable one
to tell the poisonous mushroom from the edible ones. Nor is the presence
of the so-called "death cup" a sure sign that the fungus is poisonous,
for the _Amanita caesarea_ has this cup. For the beginner, however, there
are certain general rules, which, if carefully followed, will enable him
to avoid the poisonous ones, while at the same time necessarily
excluding many edible ones.

=1st.=--Reject all fungi which have begun to decay, or which are
infested with larvae.

=2d.=--Reject all fungi when in the button stage, since the characters
are not yet shown which enable one to distinguish the genera and
species. Buttons in pasture