delivered the opinion of the court.

This was an action of ejectment. The plaintiff claimed title by virtue of a patent from the United States, dated the 3d day of November, 1857. The defendants claimed the same lands (situate in Pettis county) by entry under two duplicate receipts of the receiver of the land office for the proper district, dated September 25th, 1854, in the name of ¥m. H. Campbell. It was proved that Campbell, at the time of the entry, was a minor, under twenty-one years of age; that he had taken possession of the land and made some improvements thereon, and that his right to make the entry had been contested by the plaintiff before the Commissioner of the General Land Office on the ground that he was a minor, and- not entitled under the act of Congress to make the entry; and that for that reason the Commissioner had directed the entry to be set aside and cancelled, and that the plaintiff should be permitted to enter the land. The defendant’s entry was accordingly cancelled, and the plaintiff thereupon entered the land, and received the patent.

The third section of the act of Congress, entitled “ An act to graduate and reduce the price of the public lands to actual settlers and cultivators,” approved August 4th, 1854, (10 U. S. Stat. p. 574,) provided “ that any person applying to enter any of the aforesaid lands shall be required to make affidavit before the register or receiver of the proper land office, that he or she enters the same for his or her own use, and for the purpose'of actual settlement and cultivation, or for the use of an adjoining farm or plantation owned or occupied by him or herself, and, together with said entry, he *363or she has not acquired from the United States, under the provisions of this act, more than three hundred and twenty acres, according to the established surveys ; and if any person or persons taking such oath or affidavit shall swear falsely in the premises, he or she shall be subject to all the pains and penalties of perjury.”

The act evidently contemplates persons who are at least sui juris, and capable of acting and contracting for themselves, and not persons who are, like married women and minors, subject to the dominion of another, as the husband or the father. He must be capable of entering the land for his own use, and for the purpose of actual settlement and cultivation. It appears to have been one object of the act to encourage actual settlers and cultivators. It is obvious that these provisions did not contemplate minor children any more than married women. It is plain that to allow the head of a family to make one entry for himself, another for his wife, and another for each one of his minor children, would be to extend the operation of the act beyond the intention of Congress. We need not go so far as to say that no person whatever, under the age of twenty-one years, could be allowed to make an entry under the act. A minor may become completely emancipated from the parental control before arriving at that age, and might be capable of fulfilling all the requisites of the law. There is no proof that such was the case here.

Here the Commissioner of the General Land Office, upon an investigation of the matter, decided that this party did not come within the purview of the act, and that his entry was not made in conformity with its provisions, but was an evasion of the spirit and intent of the law. We are now asked to declare that this officer went beyond his powers, and acted without authority of law. This is not made to appear by anything contained in this record. It is proved only that he was a minor. It is not shown that he was capable of acting for himself as a person sui juris, nor that he came within the purview of the act by any construction *364that can be given to it. It has been held, in many cases, that the courts will protect a party against the exercise of unlawful authority, or misconduct, on the part of public officers, when the party himself has done everything which the law requires of him to do. It was said in Perry v. O’Hanlou, 11 Mo. 590, that the federal officers derive their authority from the laws, and that when these acts are not in conformity to law, they cannot prejudice the rights of others; and that whether the law has been complied with or not, is necessarily a question for the judicial tribunal having jurisdiction of the case ; but that where the courts have no power to look into their authority, or where their powers are judicial, or purely discretionary, their acts and decisions are conclusive, or not subject to revision by the courts. When they act in violation of law, or without authority of law, their action may be reviewed — Hill v. Miller, 36 Mo. 190. We cannot say that the action of the public officers in this case was either in violation of law, or without lawful authority. The defendants here assume the burden of showing that the patent was wholly void, or that, if valid, the defendants have the superior equitable title. They have failed to do either.

We are of the opinion, therefore, that the court erred in giving the instructions which were given for the defendant, and in refusing the second instruction asked for by the plaintiff.

It appears further, that after the cause had been tried and submitted to the court, and taken under advisement until the ensuing term, the defendants were allowed to file an amended answer, at that term, introducing new matter of defence, and stating a case for equitable relief, and then proceeded to give further instructions, and to find a verdict and give judgment without any new trial or hearing of the case.

A motion to strike out this amended answer was overruled, and an exception taken. We think such a proceeding entirely erroneous. The amendments went far beyond what *365was contemplated by the statute on this subject — R. C. 1855, p. 1253, § 3. Such amendments should not be allowed to the prejudice of the rights of the other party.

A part of this amended answer was grounded upon the act of Congress of the 3d of March, 1857, entitled “ An act to confirm certain entries of land therein named,” which had been made under the graduation act of 1854. This dct contained a- proviso “ that this act shall not be so construed as to confirm any of said entries which have heretofore been annulled and vacated by said Commissioner on account of frauds, evasion of laws, or other special cause.” Upon the evidence in this case we are of opinion that the defendants’ entries came within the exceptions contained in this proviso, and that they were not confirmed by this act of Congress. They had been annulled and vacated for the reason' that they had been made in evasion of law.

The judgment will be reversed and the cause remanded.