WASHINGTON, D. C., February 13, 1865.

Lieutenant-General GRANT, City Point:

GENERAL: As the time is approaching for organizing the cavalry for the spring campaign, I forward the following items in regard to its conditions and wants, collected by the Cavalry Bureau, to January 1, 1865:

Cavalrymen present for duty...................... 105,434

Cavalrymen present and absent.................... 160,237

Cavalry horses serviceable....................... 77,847

Cavalry horses unserviceable..................... 9,659

Cavalry horses purchased during the year......... 154,400

The number expended has been much greater than this, as the cavalry force has been less than the previous year, and, moreover, a considerable number of team and captured horses have been issued to the cavalry, and also recuperated animals. The expenditure of cavalry horses during the year has probably been less than 180,000. The waster or loss of cavalry equipments during the year is estimated as follows: Carbines expended, 93,394; pistols expended, 71,000; sabers expended, 90,000; horse equipments, 150,000. Expense of cavalry in horses, pay, forage, rations, clothing, ordnance, equipments, and transportation, $125,000,000, is certainly a pretty large sum for keeping up our cavalry force for one year. In regard to particular commands, there are in the Armies of the Potomac and the James about 10,000 mounted men, and in the Middle Division, under General Sheridan, about 12,000, which can be kept efficient by issue from here, except in case of extraordinary casualties. General Chairman has with him in the field about 6,500 men, which, since he left Atlanta, he has kept mounted by captures from the enemy. In the Department of the Ohio (now Kentucky) there were issued to General Burbridge for his Saltivlle expedition 6,000 horses. On his return 4,000 were reported lost or unserviceable. When Hood commenced his march against Nashville General Thomas' immediate command had only about 5,000 effective cavalry, but between the 1st of October and 31st of December all horses purchased in the West were sent to his chief of cavalry, the issue amounting to 23,000, and including those sent to General Burbridge during the same period, 29,000, in three months of General Thomas' entire command. As Generals Wilson and Burbridge have made requisitions since that period for 14,000 additional horses, it is presumed that about the same number were lost or disabled during that period of three months. As soon as General Thomas determined to make no farther advance during the winter, and General Canby was directed to assume active operations in the filed, orders were given to resume issues to his (Canby's) command in preference to all others. In General Canby's entire division there were about 30,000 effective cavalrymen, of which only about one-half were mounted. As, however, his cavalry force was so disproportionate to his infantry, his requisitions are for only 6,000 horses, which will soon be filled. Major-General Dodge has made a requisition for 1,000 horses to be sent to Fort Leavenworth to remount some regiments to be sent against the Indians on the Overland Mail Route. Orders have been given to fill this as soon as General Canby receives his 6,000 horses. It is proper to remark that inspection reports for the end of December shows a cavalry force in the Department of Kansas of 4,581 men present for duty and 4,386 serviceable horses. Major-General Thomas has made a requisition for 3,000 cavalry horses to be sent to General Stoneman in East Tennessee. This requisition will be filled next after those of Generals Dodge and Canby. No issue of cavalry horse have been made to the Department of Arkansas for several months, and about one-half of the cavalry there are entirely dismounted.