CALLUS, or CALLOSITY, in a general sense, any
cutaneous, corneous, or osseous hardness, whether na-
tural or preternatural; but most frequently it means
the callus generated about the edges of a fracture, pro-
vided by nature to preserve the fractured bones, or di-
vided parts, in the situation in which they are replaced
by the surgeon. A callus, in this last sense, is a sort of
jelly, or liquid viscous matter, that sweats out from
the small arteries and bony fibres of the divided parts,
and fills up the chinks or cavities between them. It
first appears of a cartilaginous substance; but at length
becomes quite bony, and joins the fractured part so firm-
ly together, that the limb will often make greater re-
sistance to any external violence, with this part than
with those which were never broken.