"Man," Phineas once replied, "don't you see that you're breaking a heart which, in spite of its apparent rugosity and callosity, is as tender as a new-made mother's?
"The Rough Road"
William John Locke
But how blind this intelligence is at times, or how wanting in judgment, may be seen when it tries to develop a callosity upon the foot as a result of the friction of the shoe, and overdoes the matter and produces the corn.
"Ways of Nature"
John Burroughs
In the case of the Macartney marriage I suspect this to have been the only kind-a kind of callosity, protective and numbing.
"Love and Lucy"
Maurice Henry Hewlett