What’s Bred in the Bone by Robertson Davies (Viking/Elisabeth Sifton : $17.95; 426 pp.)

“I’d been on the job, so to speak, since the boy was conceived on Dec. 10, 1908, at 11:37 p.m. . . . When Francis was conceived--at the very moment of the Major’s fortunate orgasm. They summoned me and said this is yours; do well by him but don’t show off.”

Speaking here is Maimas, a demon (not, as Robertson Davies makes emphatically clear, a guardian angel), in one of the many and witty glosses employed to punctuate and illuminate passages of biographical recollection concerning the life of Francis Cornish Jr., in “What’s Bred in the Bone.”

Francis’ generally lonely early years are passed in a provincial (in both senses) Canadian town. His family is prominent and ultimately quite rich, his mother and father socially active, and the family retainers an eccentric lot. There is also a severely mentally handicapped younger brother locked in an attic room.

One day Francis connects with a book on how to draw. It changes his life; he draws everything. Particularly memorable are the corpses he draws in the company of Zadok, a member of the household staff but on his own time a mortician (who always shakes hands with his clients after embalming them).

After his formal schooling concludes at Oxford, Francis apprentices with the world’s greatest restorer of paintings, Saraceni (from whom Francis learns connoisseurship), but at the same time works in his father’s profession--British Intelligence--inherits an enormous sum, and marries disastrously.

Religion--Catholic versus Protestant--plays an important role, too: “Francis’ only possible patron was the grubby Guy of Anderlecht, a Belgian who had lost all his money in a bad speculation and turned to God in his bankruptcy. Nothing there to light the flame of devotion in a boy of nine.”

Yet humor is a serious business. We may laugh when Davies tells us that Francis’ mother was one of those mothers “who is certain that if she is happy, all must certainly be well with her child,” but we also see after-images of a lonely childhood.

“What’s Bred in the Bone” has a few problems. The beginning of the book, which takes place in time after Francis’ death and invokes the angel of biography, staggers some, and the ending is much too hurried.

In between, however, Davies’ novel is absorbing, and the understated humor radiates with good sense about the way of the world. It is easy to see why he has a large and devoted following in Canada. Here, south of the border, he should be better known.