the plans for which will be found in the Report of the English Sanitary Commission. These huts, with the independent roof ventilation, were found well adapted for hospitals as well as quarters, and the results of their employment were altogether satisfactory; but it will take time to erect them, and our necessities seem to be too pressing to admit of this delay. They might, however, be put up to some extent in the worst of our campaign grounds, if military necessity requires that out men shall be kept in those positions.

Next to these huts I would invite attention again to the plan of improving out tents that I recommended in mine of the 11th December last, and perhaps in other letters, i. e., to build a pen of logs and slabs the size of the base of the tent, some 3 feet high, and then to secure the tent upon this for a roof. This plan in now in use in several camps, and wherever it has been adopted it has been found to contribute very much to the comfort of the men. In some of the camps the pit has been dug, as in the Crimea, and the tent placed over that. This I camden emphatically in the letter alluded to, and I repeat it, it is totally inadmissible. I should add to what I said before that in my opinion board floors should be furnished to all the tents must not be overcrowded. This is the tendency of all armies, and is a pernicious practice. The ventilation of tents, again is a more difficult matter then is generally supposed. This should be secured by windows, as they are termed, in the tent, and by frequently opening the tent doors or keeping them open during the day.

Most of the subsoil upon the Potomac is of clay. This is particularly so in the caps presenting the largest sick reports, and therefore the greater attention is required to be paid to its drainage. I do not believe such a soil can be sufficiently will drained in a wet season to enable us to dispense with floors to the tents, but to secure as good a drainage as practicable I would recommend each company ground should be surrounded by a ditch not less than 12 inches deep at its shallowest parts; this ditch to be 4 feet from the outside border of the tents, and to be laid out and dug under the superintendence of a competent engineer; otherwise it will be imperfectly done, and be productive of more harm than good. Supplementary ditches a few inches in depth should also surround the tens, and be carefully conducted into the main ditch. I would further suggest that the florist of the tents should be raised some three inches from the ground; that time or charcoal should be strewed over the surface of the ground, and then the floor laid without pinning, that it may be readily taken up and the ground under it policed.

Pure air cannot exist without good police. To secure this as much as possible I recommend that all impurities collected in the camps and all other impurities shall be buried not less than 12 inches below the surface. In cavalry camps the mane must be got rid of in some way, or the men will get sick. Camping grounds long occupied seem frequently to get saturated with putrescent exhalations that engender and aggravate disease. A charge of ground will often be found to arrest or diminish na endemic for a while until a new saturation of the new soil sets it in motion again. This was exemplified in Brook's brigade. A charge of camp seemed to have checked the endemic in one of his worst regiments. Gradually, however, it reappeared.

The camping ground of Berdan Sharpshooters I think should be changed on this principle, as well as that it drainage is bad. This regiment is suffering from measles, and lately severe lung complications.