health on the part of my troops through the summer and an entire absence of epidemic here, I think it would be well, in view of the coming summer, to change the regiments for the coming season, and for that purpose it will be necessary to begin now, to prevent disarranging the service. I find those necessarily kept on the lines at Carrollton suffering greatly from the malarious swamp fever, to which the debilitating effect of summer predisposes them.

To my astonishment, and against all theory, the regiment of acclimated Louisianians which I have recruited here, and one of the most healthy I had while in barracks, sent there, supposing them able to resist the effect of the malaria because of this acclimatization, have suffered from the swamp fever the most considerably of any-much more than the fresh troops-the Seventy-fifth New York, which I brought from the healthy sands of Pensacola and placed in the same locality.

I have the honor to report two regiments of Native Guards (colored) organized and mustered into the service, and one takes the field to-morrow.

I have organized an expedition, consisting of a brigade (five regiments of infantry, two batteries of artillery, and four companies of cavalry), under the command of Brigadier-General Weitzel, to move upon the western bank of the Mississippi through Western Louisiana, for the purpose of distressing the forces assembled there under General Richard Taylor.

I propose at the same time to send around some light-draught steamers, which I have been fitting for the service by protecting their boilers and engines with iron coverings, so as to prevent, if possible, the recurrence of the dreadful accident which occurred on the Mound City steamer by the penetration of her boilers by shot and by mounting them with light guns, to attack some batteries at Berwick Bay, to penetrate the waters of the bay and tributaries, and cut off the supplies of cattle for the rebel army from Texas via Opelousas and New Iberia, and to act in conjunction with Brigadier-General Weitzel. At the same time I push forward a column from Algiers, consisting of the Eighth Regiment Vermont Volunteers and the First Regiment of Native Guards (colored), along the Opelousas Railroad to Thibodeaux and Brashear City, open the railway for the purpose of forwarding supplies to General Weitzel's expedition, and to give the loyal planters an opportunity to forward their sugar and cotton to this city. I can easily hold this coming winter by this route, if I can receive early re-enforcements. Please therefore send me New England troops. The newspapers assure me that there are thousands waiting in Massachusetts. Letters from their officers are received by me begging that they may come to this department. Of course I have preference for Massachusetts troops. Those that I have behaved very well. I trust that they may be sent to me.

I should be glad if General Weitzel should be able to move upon Texas, and would suggest that an appropriate base of operations would be through Galveston, which I have just heard has surrendered to the naval force of the Union, but I have hardly a regiment which I can spare to hold it, although I propose to send one-not that I anticipate an immediate attack upon New Orleans nor that I fear it, unless I am forced to receive the debris of the Southwestern wing after the defeat of Bragg by General Buell, while if I weaken myself here I may invite an attack from such source.