Civil Code (Cap. 16), article 648

648. For the purpose of determining the abatement, the following rules shall be observed: (a) all the property of the testator, existing at the time of his death, shall be formed in one bulk, after deducting therefrom the debts due by the estate; (b) any property which has been disposed of by way of donation shall be then fictitiously added, such property being reckoned at its value at the time of the donation; (c) the disposable portion shall then be computed according to the estate thus formed, regard being had to the rights of the surviving spouse in accordance with articles 615 to 639. Subject of donation perished before death of donor not to be included in the bulk.