Digestorum libri
Ex libro XXIII
Marcellus, Digest, Book XXIII. There is no doubt that a slave can be manumitted mortis causa. You must not, however, understand if a slave is ordered to be free in this manner that he will not become so if his master should recover his health; for just as if he had been absolutely manumitted before the Prætor, when anyone thinks that he is about to die, and his death is expected, so, in this instance, freedom is granted during the last moments of the person who bestows the manumission, as his will is considered to continue to exist on account of the tacit condition of the death of the person manumitting the slave. The case is the same as if someone should deliver property under the condition that, if he dies, it shall belong to the person who receives it; since the property will not be alienated if the donor retains the same intention during his lifetime.