Not about the barren Ireland of John Millington Synge, not about the bloody and turbulent Ireland of "The Plough and the stars," but about an Ireland where the vulgarity of life is occasionally transcended by the mystery of the days when giants walked the land is Paul Vincent Carroll's "Shadow and Substance." This play, winner of the drama critics' award last year, opened in Boston last night with the original New York cast, starring Cedric Hardwicke.

Against this background of trivial gossip and narrow minds, Mr. Carroll has placed the austere Thomas Canon Skerritt, who seeks refuge from football-playing curates and "Dublin's holy hooliganism" in the cold clarity of learning and the classical grandeur of the Church. At the other angle of the triangle is Dermot Francis O'Flingsley, the rebellious schoolmaster who attacks the Canon and the Church as being cruelly aloof from the pain and squalor of life. And at the apex is Brigid, the simple child who was visited by the spirit of her namesake, St. Brigid and who, dying, left the two men she loved alone in their bitterness.

As the learned canon, Cedric Hardwicke acted with strength, irony, and restraint. Julie Haydon, playing Brigid, was naive and simple in a part which in less skilled hands might verge on Baby Snooks. And although Lloyd Gough overplayed the rebel pedagogue, Sara Allgood, uproariously funny as Miss Jemima Cooney, (a local spinster), and a superb cast more than made up for it.