_Characters._ The calculi are spherical, rough or on their opposed
surfaces flat, clear and glistening where they have become polished by
friction. They are found as a fine sand or as calculi the largest of
which have been 75 grains, and of a high density (1303 to 1484).
Bruckmüller found that they contained carbonate of lime and biliary
mucus. Verheyen found biliary resin, mucus, pigment, and a little fat.
They are rare in fat hogs in America. No diagnostic _symptoms_ have been
observed.