You can still attend Mass today, as the Oratory will celebrate High Mass tonight at 6:30pm. Faithful who assist at this Mass, or at any Institute Mass today, may obtain a plenary indulgence under the usual conditions.
Dom Gueranger says of the saint who converted 72,000 Calvinists:
God gave him to the Church at the very time that heresy was holding her out to the world as a worn-out system, that had no influence over men's minds. He raised up this true minister of the Gospel in the very country where the harsh doctrines of Calvin were most in vogue, that the ardent charity of Francis might counteract the sad influence of that heresy. If you want heretics to be convinced of their errors, said the leaned Cardinal du Perron, you may send them to me; but if you want them to be converted, send them to the Bishop of Geneva.