What is "rock milk"

Agaric \Ag"a*ric\ (?; 277), n. [L. agaricum, Gr. ?, said to be fr. Agara, a town in Sarmatia.]

1. (Bot.) A fungus of the genus Agaricus, of many species, of which the common mushroom is an example.

2. An old name for several species of Polyporus, corky fungi growing on decaying wood.

   Note: The ``female agaric'' ( Polyporus officinalis) was renowned as a cathartic; the ``male agaric'' ( Polyporus igniarius) is used for preparing touchwood, called punk or German tinder.

   Agaric mineral, a light, chalky deposit of carbonate of lime, sometimes called rock milk, formed in caverns or fissures of limestone.