"Quo Vadis" is colossal, all right; it's a colossal bore. M-G-M assembled a couple of dozen amiable lions, lots of chariots and other Roman go-carts, 30,000 guys in bed-sheets, and a balsa wood city, but they never did anything with the happy throng.

Instead, half a dozen of the more articulate members of this cast of thousands traded truisms in a conversational sham battle that dragged on for dangerously close to three hours. The screen play for "Quo Vadis" is talky enough to have been written by G. Bernard Shaw, except that it sounded a good deal more like Edgar A. Guest.

There were, in fact, only two places where enough action took place on the screen to rouse the drowsing audience: the burning of Rome scene and the one where the lions are supposed to dine on prime ribs of martyr. The former is indeed an impressive spectacle, but in the latter, the lions have so little actual contact with the Christian martyrs that the whole thing might well have been taken on a Friday.

The acting, or speech-making, in Q-V is in keeping with the Guestian level of the dialogue. Robert Taylor, as the Latin hero, runs the emotional gamut, with his accustomed impassive Cherokee stare. Deborah Kerr, the titian-haired heroine, brings to her role the solemn uncomprehending dogmatism of a Radcliffe freshman discussing the subjects in question--sex and religion. But the prize ham of the evening goes to Peter Ustinov, who makes such a hash out of Nero that you wind up feeling sorry for the old boy.

Plotwise, Kerr gets Taylor, Taylor gets religion, the mob gets Nero, and the audience gets restless. How Metro could spend so much money on "Quo Vadis" and come up with such a mish-mosh of didactic dullness will of course remain one of the great mysteries of our time. Never have so many paid so much to see so little.