SECTION 3Substitution of HeirsArticle 857. Substitution is the appointment of another heir so that he may enter into the inheritance in default of the heir originally instituted. (n) Article 858. Substitution of heirs may be: (1) Simple or common; (2) Brief or compendious; (3) Reciprocal; or (4) Fideicommissary. (n) Article 859. The testator may designate one or more persons to substitute the heir or heirs instituted in case such heir or heirs should die before him, or should not wish, or should be incapacitated to accept the inheritance. A simple substitution, without a statement of the cases to which it refers, shall comprise the three mentioned in the preceding paragraph, unless the testator has otherwise provided. (774) Article 860. Two or more persons may be substituted for one; and one person for two or more heirs. (778) Article 861. If heirs instituted in unequal shares should be reciprocally substituted, the substitute shall acquire the share of the heir who dies, renounces, or is incapacitated, unless it clearly appears that the intention of the testator was otherwise. If there are more than one substitute, they shall have the same share in the substitution as in the institution. (779a) Article 862. The substitute shall be subject to the same charges and conditions imposed upon the instituted heir, unless and testator has expressly provided the contrary, or the charges or conditions are personally applicable only to the heir instituted. (780) Article 863. A fideicommissary substitution by virtue of which the fiduciary or first heir instituted is entrusted with the obligation to preserve and to transmit to a second heir the whole or part of the inheritance, shall be valid and shall take effect, provided such substitution does not go beyond one degree from the heir originally instituted, and provided further, that the fiduciary or first heir and the second heir are living at the time of the death of the testator. (781a) Article 864. A fideicommissary substitution can never burden the legitime. (782a) Article 865. Every fideicommissary substitution must be expressly made in order that it may be valid. The fiduciary shall be obliged to deliver the inheritance to the second heir, without other deductions than those which arise from legitimate expenses, credits and improvements, save in the case where the testator has provided otherwise. (783) Article 866. The second heir shall acquire a right to the succession from the time of the testator's death, even though he should die before the fiduciary. The right of the second heir shall pass to his heirs. (784) Article 867. The following shall not take effect: (1) Fideicommissary substitutions which are not made in an express manner, either by giving them this name, or imposing upon the fiduciary the absolute obligation to deliver the property to a second heir; (2) Provisions which contain a perpetual prohibition to alienate, and even a temporary one, beyond the limit fixed in article 863; (3) Those which impose upon the heir the charge of paying to various persons successively, beyond the limit prescribed in article 863, a certain income or pension; (4) Those which leave to a person the whole or part of the hereditary property in order that he may apply or invest the same according to secret instructions communicated to him by the testator. (785a) Article 868. The nullity of the fideicommissary substitution does not prejudice the validity of the institution of the heirs first designated; the fideicommissary clause shall simply be considered as not written. (786) Article 869. A provision whereby the testator leaves to a person the whole or part of the inheritance, and to another the usufruct, shall be valid. If he gives the usufruct to various persons, not simultaneously, but successively, the provisions of article 863 shall apply. (787a) Article 870. The dispositions of the testator declaring all or part of the estate inalienable for more than twenty years are void. (n)