Firmissimam Constantiam §18

¹⁸ Nor can We fail to mention a duty which in these recent times is ever increasing in importance: the assistance for Mexicans who have emigrated to other countries, who, torn away from their country and their traditions, more easily become prey to the insidious propaganda of the emissaries seeking to induce them to apostatize from their Faith. An arrangement with your zealous confreres of the United States of America will bring about a more diligent and organized care on the part of the local clergy and will assure for the Mexican emigrants those social and economic provisions which are so well developed in the Church in the United States.