From the above data it is seen that the mushroom does not contain anything like the amount of protein found in beefsteak. It has one-third more water, one-sixth as much protein, and only one-fortieth as much fat. Beefsteak contains no carbohydrates except less than one percent of glycogen, while the amount of carbohydrates in the mushroom varies from 1.5 to 3.5 percent. It is evident that the mushroom is principally valuable as a condimental substance and not as a food product.
Distinction between Poisonous and Edible Varieties.
—It has already been stated that only the expert is able to distinguish between the poisonous varieties of mushrooms and those that are edible. Even the skilled botanist, as well as the expert, may sometimes make mistakes in this matter. Hence the only perfectly sure method of protection against the poisonous varieties is the eating of only those which are cultivated and which are known to be free of poisonous properties. On the other hand, the wild variety, by many connoisseurs, is much more highly valued as being more delicate and palatable. It should also be remembered that the cultivation of mushrooms is not very widely extended, and if the supply of the wild variety should be excluded there would be a great diminution of the quantity which is accessible to the consumer. This would be an especial hardship in the United States, where mushrooms grow wild over such wide areas and so abundantly and where the cultivation of them as compared with some other countries is somewhat restricted. There are some general characteristics by means of which a distinction can be made between the edible and the poisonous varieties.
The following rules are given for the rejection of the probably poisonous mushroom by George Francis Atkinson (“Studies of American Fungi—1900”): “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 someone 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 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 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.
“1st.—Reject all fungi which have begun to decay, or which are infested with larvæ.
“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 lands which are at the surface of the ground, and not deep-seated in the soil, would very likely not belong to any of the very poisonous kinds.
“3d.—Reject all fungi which have a cup or sac-like envelope at the base of the stem, or which have a scaly or closely fitting layer at the base of the stem and rather loose warts on the pileus, especially if the gills are white. Amanita cæsarea, however, has a sac-like envelope at the base of the stem and yellow gills as well as a yellow cap, and is edible. Amanita rubescens has remnants of a scaly envelope on the base of the stem and loose warts on the cap, and the flesh, where wounded, becomes reddish. It is edible.
“4th.—Reject all fungi with a milky juice unless the juice is reddish. Several species with copious white milk, sweet or mild to the taste, are edible.