portal of Saint-Denis, and the nave of Saint-Germain des Pr�s. There is the charming, half-Gothic chapter-house of Bocherville, where the Roman layer extends half way up. There is the cathedral of Rouen, which would be entirely Gothic if it did not bathe the tip of its central spire in the zone of the Renaissance.

Facies non omnibus una,

No diversa tamen, qualem, etc.

Their faces not all alike, nor yet different, but such as the faces of sisters ought to be.

However, all these shades, all these differences, do not affect the surfaces of edifices only. It is art which has changed its skin. The very constitution of the Christian church is not attacked by it. There is always the same internal woodwork, the same logical