will always be a free tenement and, all other heirs being excluded, will revert to  the donor, since the condition was not satisfied.1 Thus a condition is joined to a  modus. By the modus a gift may be made to the husband and wife and the heirs  of the wife only, or to the husband and wife and the heirs of the husband only.  Also to the husband and wife and their common heirs, if there are such, and if not,  then to the heirs of the survivor.2
Gifts may be made subject to a modus with a condition attached.
 If one says, I give to such a one so much land etc. that he give me so much, or  that he find me in necessaries, though not entirely free, a gift of that kind is  simple and absolute and, if followed by livery, cannot be revoked; he who transferred  can sue only for this, that the donee hold to his agreement and do what he  promised.3 But if, when the gift is first made, a condition is at once attached to  it, that unless the recipient holds to his agreement the transferor may at once  put himself back into the land and hold it to himself and his heirs, quit of the  recipient and his heirs, [it will be otherwise].4 If he afterwards puts himself in  seisin [and] the donee arraigns an assise of novel disseisin against him, it must first  be asked whether he who took the tenement has found the donor in necessaries to  an extent that ought to satisfy him.5 If he has not, the assise falls; if he has, he  will recover by the assise. If he has not provided sufficiently and the transferor  cannot put himself back into seisin by force of the condition, an action [based  upon] the agreement6 will be given him for recovering his seisin; 7if he is in possession  by his own efforts he may maintain himself there by an exception based upon the  agreement. But what if he who took under a limitation of this kind gives the land  over to another; though it is subject to a condition, quaere whether he who [first]  transferred may eject the alienee since the agreement does not touch him. It  appears at first sight that he may, for the thing seems to be bound as well as the  person, so that it cannot be transferred to another without its burden, [and] thus  that if [the second feoffee] is ejected, though without judgment, he will not recover.  But in truth the obligation is personal, and an agreement made between certain  persons does not bind others, only those between whom it was made, nor was it  expressly stated from what tenement the necessaries ought to be found, from  [this] any more than from that, and therefore the tenement is neither charged nor  burdened.8 How must the plaintiff aid himself if he cannot eject one so enfeoffed  nor put himself in seisin in accordance with the agreement nor bring an action  against him on the agreement? He must sue him, it is submitted, with the