http://sedevacantist.com/newmass/qtvjmcn.htm

 2)  THE NECESSITY OF PROPER, DETERMINATE FORMS FOR SACRAMENTS

Necessity of Specific, Determinate Matter

11.  As everyone knows, for any sacrament to be administered validly, it is necessary that the proper matter be used; for example, water for Baptism, bread and wine for the Holy Eucharist.

12.  St. Thomas Aquinas explains why specific, determinate things are required for the proper matter of the sacraments: "Since, therefore, the sanctification of man is in the power of God Who sanctifies, it is not for man to decide what things should be used for his sanctification, but this should be determined by Divine institution.  Therefore in the sacraments of the New Law, by which man is sanctified according to I Cor. vi. 11, "You are washed, you are sanctified," we must use those things which are determined by Divine institution." (Summa Th., III, Q. 60, Art. 5).

13.  Thus no mere man may dare attempt to arrogate to himself the right to change the proper matter of a sacrament, for "we must use those things which are determined by Divine institution."

Necessity of a Specific Determinate Form Even Greater

14.  Now if a specific, determinate matter is required for the validity of a sacrament, greater still is the necessity of a specific, determinate form.  "And therefore in order to insure the perfection of sacramental signification it was necessary to determine the signification of the sensible things (i.e., the matter) by means of certain words."  (Summa Th., III, Q. 60, Art. 6).

15.  "As stated above, in the sacraments the words are as the form, and sensible things areas the matter.  Now in all things composed of matter and form, the determining principle is on the part of the form.  . . . Consequently, for the being of a thing the need of a determinate form is prior to the need of determinate matter. . .  Since, therefore, in the sacraments determinate sensible things are required, which are as the sacramental matter, much more is there need in them of a determinate form of words." (Summa Th., III, Q. 60, Art. 7, emphasis added).

16.  And so, similarly as above, mere men may not dare usurp the right to change the proper form of a sacrament.