Colonel GEORGE D. RUGGLES,

Assistant Adjutant-General, Hdqrs. Army of the Potomac:

COLONEL: I respectfully invite your attention to the propriety of having a reserve train of ambulances kept by the quartermaster's department, from which deficiencies in the corps in the corps may be promptly filled and to be subject to the order of the medical director of the army whenever emergency may demand. Repairs of the ambulances of this army were very thoroughly made prior to the campaign of 1864, and a few new ones issued. To a great extent the ambulances were old at that time, and it is the more to be expected that a number of them will require to be turned in as worn out. During the battle of the Wilderness the spring wagons in the army were turned over to the medical directors, and have since been available, but their number is quite limited. Army wagons, whenever empty and available, were used for transportation of men from the field hospitals to the base. Accurate statement cannot be given, but the transport service rendered by ambulances and wagons in three months of the past campaign, so far as data are preserved, was in the relation of 3, 1518 ambulances and 2,233 wagons. The number of ambulances in the spring of 1864 was about 800. It was necessary to send to Washington in May for additional ambulances for use in Fredericksburg and in the army. There are now only 522 in all the corps and commands. After the Sixth Corps left this section for the Shenandoah Valley, and before the extension of the surface railroad, I found it necessary to use the Sixth Corps ambulance train frequently. It was ordered up prior to the explosion of the mine July 30 and in the occupation of the Weldon railroad August 18-25. But for the timely employment of the Sixth Corps train the suffering and delay would have been very great. I have now no available reserve train, and at the same time a less number on hand in the several corps than formerly. It will be proper in my opinion, that the quartermaster's department take measures to procure 200 ambulances and harness for contingent use and for issues to supply deficiencies and possible losses. Should movement be made to any considerable distance, or a grand battle be delivered by the enemy, these ambulances would be required. In view of the coming campaign, and possible co-operative movements of our armies, and their magnitude, I deem it proper to call up the subject.

I am, colonel very respectfully, &c.,

THS. A. McPARLIN,

Bvt. Lieutenant Colonel, U. S. Army, Medical Director, Army of the Potomac.