OFFICE OF F Vicksburg, July 16, 1870. To the County and Municipal Boards of Health in the State of Mississippi: Gentlemen; In view of the recent outbreak of yellow fever at Memphis, indicating the possible occurrence of another epidemic of this dreaded disease, the State Board of Health, [convened at Jackson on the 15th instant, to consider what measures shall be adopted to avert, if possible, the impending calamity. After mature consideration of the whole subject, the Board have deemed it advisable to adopt, for their guid- ance, the Rules and Regulations provided by the National Board of Health, with a view to securing uniformity of action in all matters pertaining to quarantine. We earnestly recommend that you second our efforts to aid the National Board of Health in establishing a comprehensive system of quarantine that is designed to afford ample pro- tection to communities against the introduction and propagation of contagious and infectious diseases, It is_.evident that one of two courses must adopted in the event of an epidemic of Yellow Fever: Either absolute non-intercourse must be decreed against all infected points, regardless of their number and locality; or some provision must be made for securing necessary commercial intercourse under such wise and stringent regula- tions as may reduce the danger of infection to a minimum. The experiment of apparent absolute non-intercourse was tried on a small scale during the last epidemic, by small, isolated communities, usually at some distance from the great lines of traffic, and seemed to afford satisfac- tory results; but it is evident that in large communities, as a State, absolute non-intercourse cannot be maintained without inducing disasters probably more to be dreaded than an incursion of epidemic disease. It is believed that, in this age of active commercial intercourse, the agencies by which this is effected, cannot be suddenly arrested or destroyed without imposing intolerable burdens and inflicting an almost irreparable damage upon society. In a word, we believe absolute non-intercourse, when attempted by a whole State, will be found to be utterly impracticable. It was not possible to adopt this plan during the late epidemic, because considerations of policy, as well as humanity, demanded that the ordinary modes of communication with the outside world, on which our helpless situation ren- dered us peculiarly dependent, should not be seriously interrupted. If this be true, it only remains for us to devise some practicable and efficient plan by which this communication can be had with the least possible danger to ex- posed districts. We believe that the system proposed by the National Board of Health will effect all that can be desired in this regard, provided uniformity of action can be secured by its universal adoption and enforcement by the various State, County and Municipal Boards of Health. O. A. RICE, M. D., B. F. KITTRELL, M. D., Secretary, pro. tem. President State Board of Health.