Massachusetts General Laws Part II. Real and Personal Property and Domestic Relations (Ch. 183-210) Ch. 184, § 3

A contingent remainder shall take effect, notwithstanding any determination of the particular estate, in the same manner in which it would have taken effect if it had been an executory devise or a springing or shifting use, and shall, as well as such limitations, be subject to the rule respecting remoteness known as the rule against perpetuities, exclusive of any other supposed rule respecting limitations to successive generations or double possibilities; but this section, except so far as declaratory of existing law, shall apply only to instruments executed on or after April sixth, nineteen hundred and sixteen, and to wills and codicils revived or confirmed by a will or codicil executed on or after said date.