Whilst he fulfils the purpose for which she made him, he is welcome to his dreams, his follies, his ideals, his heroisms, provided that the keystone of them all is the worship of woman, of motherhood, of the family, of the hearth.
There are no more uses of "keystone" in the book.
Show samples from other sources
the keystone of campaign reform was the ban on soft money
Friendship with Canada is the keystone in the arch of America’s foreign relations.