[001] 1I give that you give, as I give you a Digest that you give me a Code, so that if [002] I deliver a Digest, you are bound to deliver me a Code. Or if I say, I give that [003] you do, that is, I give you a Code that you cause a Digest to be written for me. Or [004] I do that you give, that is, I build you a house that you give me a Code. Or I do [005] that you do, that is, I build you a hall that you build me a chamber. These gifts [006] subsist under a modus and bind the contracting parties, so that if I give or do, you [007] are bound to give or do as you agreed. But they do not enable me to recall what I [008] have given if you are unwilling to do what you promised. 2I can only sue [to compel [009] you] to do,3 unless it is otherwise agreed at the beginning. For to this gift subject to [010] a modus a condition may be added at the outset, as if I say, And if you do not give [011] or do what you agreed that I may recall what I gave, or recover the charges [012] incurred in connexion with what4 I did. If no condition is added, however, I [013] cannot.5
If a gift is made subject to a condition.
[015] A gift may be made subject to a condition without6 a modus, as where I say, I [016] give you that thing if something be done or not done, if the condition relates to [017] the future, 7for though [they may be uncertain to us] the present and past are not [018] in suspense as the future is; the condition either invalidates the obligation at once [019] or defers it in no way.8 Then either9 the condition is possible or impossible.10 If [020] possible and within the donee's power,11 as where I say, I give you such a thing [021] if you give me ten, the gift is good but suspended until the condition occurs,12 [022] so that if you claim the thing I can except that you have not given me ten. 13If [023] the condition is impossible, as I give you that thing if you touch the sky with your [024] finger, the gift is not valid, [but if I say if you do not touch the sky, it is valid], [025] as though no condition had been imposed.14 A gift is not valid ab initio but in [026] suspense if the condition is placed in the power of another, as I give you this [027] thing if Titius wishes me to, or if he so decides, or does such an act, for unless [028] he does so the gift will not be good. So if the condition is fortuitous, as I give [029] you such a thing if a ship arrives from Asia, or if Titius is made consul; the gift [030] will be in suspense because such gifts hang upon the vagaries of fortune.15 If the [031] condition is mixed, as where it is partly within the donee's power and partly [032] fortuitous,16 and disjunctive, as I give you this thing if you give me ten [or a ship [033] arrives from Asia], it suffices if one of the conditions is fulfilled. 17But if several [034] conditions are annexed conjunctively, as if this and that be done, they all must [035] be satisfied; if disjunctively, (as said above) it is sufficient to comply with one or [036] the other of them.1819Some conditions are express and in negative words, as if [037] Titius is not heir be you heir,20 or if