MODO. - A clause appended to a contract or an act of liberality, imposing a burden on one of the contracting parties or on the beneficiary of the act of liberality.
As an incidental element, the *modo* or burden enters into various legal transactions (donations, legacies, institution of heirs, acts of liberality in general), normally with the effect of allocating part of the benefit of the liberality to third parties outside the transaction or to purposes of public utility.
The content of the modal disposition is generally expressed in Latin with the conjunction *ut*; in Italian with "perché" ("so that"), "ma" ("but"), etc. (e.g.: "Leave a field to Titius, *perché* he may have three Masses celebrated every year for me"; or: "but Titius will have Masses celebrated", etc.).
The appending of the *modo* does not alter the typical effects of the transaction, but adds others to them. It is therefore distinguished from a condition (v.) because, whereas the latter is a limitation placed on the effects of the transaction, making them dependent on the occurrence of a future and uncertain event, the *modo* is simply an accessory volitional act to the principal one that determines the act of liberality, which takes effect immediately, without waiting for the fulfillment of the burden (the validity of the act, that is, does not depend on the fulfillment of the burden, even though sometimes, for reasons of expediency, the legislator provides that non-fulfillment causes the termination of the principal disposition). The *modo* also differs from the counter-performance in onerous contracts, inasmuch as, whereas performance and counter-performance are made with a view to each other and are therefore on the same level, the burden is something separate, secondary with respect to the act of liberality, in which it has its cause.
In itself, non-fulfillment of the *modo* would give only the right to those with an interest to demand fulfillment of the obligation contained therein; in other words, the *modo* does not terminate the act but compels performance. When termination of the act is provided for by the benefactor or the contracting party in case of non-fulfillment of the *modo* or burden, then one falls back into the figure of an improper condition or reservation, which involves the formulation of a hypothesis that, if it does not correspond to reality, produces the nullity of the act subordinate to it (cf. Cod. civ. ital., art. 793).
It is here that in practice the doubt may most easily arise whether one is dealing with a *modo* or an improper condition. And the resolution can be given only by the will of the donor or contracting party; from this, as canonistic jurisprudence holds, the difference between *modo* and improper condition is to be measured.
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