the land the husband and wife together hold in dower of the gift of her first husband.  Though1 the warrantor wishes to make the gift, he cannot put the donee into vacant  seisin, since husband and wife are the same body and flesh. Nor, for the same reason,  can he attorn the service of the wife to her husband2.
By a gift one causa possidendi is sometimes changed to another.
 3By a gift one causa possidendi is sometimes changed into another, [If one at first  has a bare use in some thing, by grant of him who has the proprietas he may have a  usufruct. If at the outset he has a usufruct and a term, he may, before the term has  expired and while he is thus in possession, have a free tenement.]4as where to one  having a free tenement, as to one who holds in dower, or by the law of England or the  like,5 it is granted, while he is thus in seisin, [without putting himself out of seisin  provided some ceremony is observed at the making of the change, lest the gift fail  for lack of proof,]6 that he hold it in fee and thenceforth have the proprietas, for  he [who has the proprietas] may7 of a free tenement make the possessor a fee. 8<The  ceremony is [not] required in order that what one first has for a term may be given9  him in fee, [for] whether the donor and donee are present or absent the causa possidendi  is changed ipso jure, [but] for this reason, because it is one thing to have only a  right of use and a usufruct, and a very different thing to have dominium and proprietas.  Hence it is safer that some ceremony be observed in order to prove the  change, for unless it is, proof may fail though there is no absence of right.> <A  donor and true lord, with the tenant's consent, may change one causa possidendi  to another, without any change of possession, [When he is once in possession, it is  not necessary to take back the thing once given in order to change the causa, as  though the gift had to be made de novo, because if the true lord could grant him the  thing in fee, without any change of possession, though10 he entered by intrusion or  disseisin [and] his possession is wrongful, a fortiori he may do so if it is rightful.]  unless it is to the prejudice of another,11 as where a gift is made to a minor, whose  causa cannot be changed to his damage and disadvantage, only to the improvement  of his position.12 It cannot be changed within age to his damage, that is, that he have  for life what was earlier given him to himself and his heirs, or [so that] what was  given him in fee or for life be transferred to another, to