CAPE GIRAARDEAU, MO., January 29, 1862.

General GRANT, Cairo:

Captain Murdoch came in yesterday with twenty-five prisoners from Castor Creek. Major Herr, late of Jeff. Thompson's command, arrived last night with a flag of truce from Thompson to arrange for exchange of prisoners.

L. F. ROSS,

Colonel, Commanding.

HEADQUARTERS,
Cape Girardeau, January 30, 1862.

Brigadier General M. JEFF. THOMPSON.

GENERAL: In reply to yours of the 27th instant I desire to say that all matters pertaining to exchange of prisoners and the light in which the parties captured at Bloomfield and Dallas are to be regarded will be referred to the district commandant, Brigadier-General Grant.

I am, very truly, your obedient servant,

L. F. ROSS,

Colonel Seventeenth Illinois Volunteers, Commanding.

SAINT LOUIS, January 31, 1862.

Brigadier General U. S. GRANT, Commanding, Cairo.

GENERAL: You are authorized to exchange with the enemy any prisoners of war you may now have or may hereafter capture.

You may also inform General Polk that on releasing any of our prisoners he may have you will release an equal number, grade for grade, each party sending the released prisoners under a flag of truce to eh lines of the other party.

When the same grade cannot be given it is proposed to give two of the grade next below, that is for one colonel give two lieutenant-colonels, or four majors, or eight captains, &c. This is the basis proposed by General Sterling Price and will be followed till some other rule shall be adopted.

Endeavor if possible to effect the exchange of Captain Prime and others at Nashville, Tenn. I have prisoners of war here to fill any cartel you may succeed in negotiating.

Where an exhange is made a full descriptive list must be forwarded to these headquarters giving name, rank, company, regiment and corps.

All prisoners of war not quilty of crimes against the laws of war will be supplied when necessary the same as our own soldier and submitted to no more restraints than may be deemed necessary for their safe-keeping. Where quilty of crime they will not be exchanged but will be kept in custody.

Very respectfully, your obedient servant,

H. W. HALLECK,

Major-General.