When the plants are dry they are very brittle and must be handled carefully. When removed from the drier many kinds soon absorb enough moisture to become pliant so that they are not easily broken. Others remain brittle. They may be put away in small boxes; or pressed out nearly flat, _not so as to crush the gills_, and then put in paper packets. The plants which do not absorb sufficient moisture from the air, so that they are pliant enough to press, can be placed in small boxes or on paper in a large box with peat moss in the bottom, and the box then closed tightly until they absorb enough moisture to become flexible. The plants must not get wet, and they should be examined every half hour or so, for some become 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 cæsarea_ 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.