The distinction between the public and the secret parts of divine service, the missa catechumenorum and the missa fidelium, and the mysterious veil which piety or policy had cast over the latter are very judiciously explained by Thiers, Exposition du Saint Sacrement,1. i. c. 8-12, p. 59-91; but as on this subject the papists may reasonably be suspected, a Protestant reader will depend with more confidence on the learned Bingham, Antiquities, 1. x. c. 5.