(4) _Cession of jurisdiction_ over a given portion of territory as surety for the performance of a certain act, payment of an indemnity or the like, has for some years been a method of acquiring temporary jurisdiction which frequently becomes permanent.
(_e_) =Prescription=, or the acquisition of territory by virtue of long-continued possession, is similar to prescription in public law as applied to the acquisition of property by persons. The recognition of this principle prevents many disputes over jurisdiction of territory which originally may have been acquired in a manner open to question, _e.g._ the holding of the territory by the states parties to the partition of Poland may through long-continued possession be valid by prescription if not by the original act.
In regard to prescription, it should be observed that (1) it is a title valid only against other states. The inhabitants do not necessarily lose rights originally possessed. (2) This method avoids perpetual conflicts on ground of defect of original title. (3) Prescription may be considered as effective when other states have for a considerable time made no objection, threatening the exercise of jurisdiction by the state in possession. While some authors deny this right, it is generally admitted in fact, and by most of the leading authorities acknowledged in theory.[130]
(_f_) When land areas in the neighborhood of the boundary of a state are changed, territory may be acquired by =accretion=. (1) Land formed by _alluvium_ or other cause near the coast of a state is held to belong to that state. Lord Stowell, in 1805, held that mud islands formed by _alluvium_ from the Mississippi River should for international law purposes be held as part of the United States territory.[131] In general, _alluvium_ becomes the property of the state to which it attaches, following the Roman law.[132] (2) Where a river is the boundary, the rule is well-established that islands formed on either side of the deepest channel belong to the state upon that side of the channel; an island formed mid-stream is divided by the old channel line. (3) When a river's channel is suddenly changed so as to be entirely within the territory of either state, the boundary line remains as before in the old channel. So also the boundary line of territory is not changed, even if the bed of a lake be changed.