Exclusive jurisdiction be, and the same is hereby ceded to the United States over all the territory now owned by the United States and comprised within the limits of the Military Reservation of Fort Sill, in Comanche County, as declared from time to time by the President of the United States, and over such lands as may hereafter be acquired for the enlargement of said reservation; provided, however, that the State of Oklahoma reserves the right to serve civil or criminal process within said reservation in suits or prosecutions for or on account of rights acquired, obligations incurred, or crimes committed in said state but outside of such cessions and reservation; provided, further, that the State of Oklahoma reserves the right to tax railroad companies and other corporations and their franchises and property on said reservation; and provided, further, that the jurisdiction herein ceded shall continue no longer than the United States shall own and hold said reservation for military purposes.