7 Let us now see how the law stands if some part remains undisposed of, and yet each heir has his share assigned to him—if, for instance there are three heirs instituted, and each is assigned a quarter of the inheritance. It is evident that in this case the part undisposed of will go to them in proportion to the share each has assigned to him by the will, and it will be exactly as if they had each been originally instituted to a third. Conversely, if each heir is given so large a fraction that the as will be exceeded, each must suffer a proportionate abatement; thus if four heirs are instituted, and to each is assigned a third of the inheritance, it will be the same as if each had been originally instituted to a quarter.
8 If more than twelve ounces are distributed among some of the heirs only, one being left without a specific share, he will have what is wanting to complete the second as; and the same will be done if more than twenty-four ounces are distributed, leaving him shareless; but all these ideal sums are afterwards reduced to the single as, whatever be the number of ounces they comprise.
9 The institution of the heir may be either absolute or conditional, but no heir can be instituted from, or up to, some definite date, as, for instance, in the following form—'be so and so my heir after five years from my decease,' or 'after the calends of such a month,' or 'up to and until such calends'; for a time limitation in a will is considered a superfluity, and an heir instituted subject to such a time limitation is treated as heir absolutely.
10 If the institution of an heir, a legacy, a fiduciary bequest, or a testamentary manumission is made to depend on an impossible condition, the condition is deemed unwritten, and the disposition absolute.
11 If an institution is made to depend on two or more conditions, conjunctively expressed,—as, for instance, 'if this and that shall be done'—all the conditions must be satisfied: if they are expressed in the alternative, or disjunctively—as 'if this or that shall be done'—it is enough if one of them alone is satisfied.
12 A testator may institute as his heir a person whom he has never seen, for instance, nephews who have been born abroad and are unknown to him: for want of this knowledge does not invalidate the institution.
TITLE XV. OF ORDINARY SUBSTITUTION
A testator may institute his heirs, if he pleases, in two or more degrees, as, for instance, in the following form: 'If A shall not be my heir, then let B be my heir'; and in this way he can make as many substitutions as he likes, naming in the last place one of his own slaves as necessary heir, in default of all others taking.
1 Several may be substituted in place of one, or one in place of several, or to each heir may be substituted a new and distinct person, or, finally, the instituted heirs may be substituted reciprocally in place of one another.