The Manassas corrospondont ot tho New Orleans Picayune, writing on the lOth, says : "Tho vveather ior the pnst four day& bas boen intensely hot. I fear we nmy havo much siukneiis in September, t' great attention is not paid to the preservalioii of health. Tho atmosphero is improgiiiited with all kinds of impurities, arisiog frorn tho battle-fiold and the camp. The totid ndors proceeding from the deeaying bodiea ot men and beasts, and of the offol ond filth of camp, are cnotigh Li produce fevers and epidemk. He wl'o has never visited a fresh baltle-field and a camp on a grand peale can never imagina the immense amount of decaying matter Ecnttered about. Thiö putrid mass, exposed to the burning hents of August and September, must have a vory deteterioua etlect iipon the hoalth of the. soldier. The (ilüi at Manassas is bo yond conception. No ono ewmiB to conaidtT what wil] be the result of iln nccumulation and deonmpoaltiop. Tho soldier talks over hi.s battles, and looks forward ior otlier victories. Deattí is disregarded, and a braman corpse is regarded scarcely more than thatof a dumb beast. Tho General is actively engaged in planning otlier campaigns, or prepariflg f'or defenw, and alt seem to foiget and orerlook tlie sanitary lavvs whicli must be observad to preserve health."