Captain MacDonald declined to give his parole, and has, therefore, been retained as a prisoner of war. He was transferred on the 13th instant to the custody of the officer commanding the Illinois troops at Casseyville, Ill., some ten miles from Saint Louis. I transmit herewith a copy of my answer to the writ of habeas corpus.

The case has been postponed until Monday next, when it will come up before the U. S. court at its regular session.

I am, sir, very respectfully, your obedient servant,

WM. S. HARNEY,

Brigadier-General, Commanding.

[Inclosure.]

SAINT LOUIS, May 15, 1861.

Honorable Judge THEAT,

Judge of the U. S. Court, Eastern District:

In response to the writ of habeas corpus yesterday served on me commanding me to bring before his honor one Emmett MacDonald, I have to say that Mr. MacDonald, the person described in the writ, is not imprisoned or kept in confinement by me, nor is he under my control or command, nor has he been imprisoned or confined or so under my control or command at or since the issuing of this writ.

In making this return to the writ of habeas corpus issued by you commanding me to produce the body of Emmett MacDonald, and in making my response to the same I avail myself of the opportunity thus presented to express my profound regret of the state of things existing in this community. I declare my wish to sustain the Constitution and laws of the United States and of the State of Missouri. But while making this declaration I find myself in such a position that in deciding upon a particular case I must taken to what I am compelled to regard as the higher law, even by so doing my conduct shall have the appearance of coming in conflict with t he forms of law.

With respect to the transaction which took place at Camp Jackson near this city on the 10th instant I have to say that it happened prior to my arrival here and before my assumption of the command of this department. While I am not therefore responsible for the proceedings at that camp, and under ordinary circumstances should not feel at liberty to comment upon them officially, I am not disposed in the existing state of things to shrink from the responsibility of acknowledging that my predecessor in command saw in the proclamation of the President of the United States ordering the dispersion of all armed rebels hostile to the United States, as described in the proclamation, a high and imperative duty imposed upon him with respect to the camp in question, the evidence of its treasonable purposes having been to his mind indisputably clear. His action in the premises I recognize therefore as imposing upon me the obligation of assuming the consequences of his proceedings so far as to abstain from pursuing any course which, by implication, might throw a doubt upon the sufficiency of his authority.

Upon looking into the circumstances attending the detention of Emmett MacDonald I find they are such if I had him in charge that I could not give orders that might set him at large, unless some sufficient evidence should be furnished that he was not of the number of those in Camp Jackson who gave to that camp its character by which it came under the class of disaffected men hostile to the Government of