Good mushrooms are only found in clear open fields where the air is pure and unconfined. Those that grow in low damp ground, or in shady places, are always poisonous. Mushrooms of the proper sort generally appear in August and September, after a heavy dew or a misty night. They may be known by their being of a pale pink or salmon colour on the gills or under side, while the top is of a dull pearl-coloured white; and by their growing only in open places. When they are a day old, or a few hours after they are gathered, the reddish colour changes to brown.
The poisonous or false mushrooms are of various colours, sometimes of a bright yellow or scarlet all over; sometimes entirely of a chalky white,stalk, top, and gills.
It is easy to detect a bad mushroom if all are quite fresh; but after being gathered a few hours the colours change, so that unpractised persons frequently mistake them.
It is said that if you boil an onion among mushrooms the onion will turn of a bluish black when there is a bad one among one them. Of course, the whole should then be thrown into the fire. If in stirring mushrooms, the colour of the silver spoon is changed, it is also most prudent to destroy them all.