The innumerable swine which are reared in the vast forests of the interior, at no expense to the inhabitants, are the great staple of Servian product and export. In districts where acorns abound, they fatten to an inconceivable size. They are first pushed swimming across the Save, as a substitute for quarantine, and then driven to Pesth and Vienna by easy stages; latterly large quantities have been sent up the Danube in boats towed by steam. Another extensive trade in this part of the world is in leeches. Turkey in Europe, being for the most part uncultivated, is covered with ponds and marshes, where leeches are found in abundance. In consequence of the extensive use now made of these reptiles, in preference to the old practice of the lancet, the price has risen; and the European source being exhausted, Turkey swarms with Frenchmen engaged in this traffic. Semlin and Belgrade are the entrepots of this trade. They have a singular phraseology; and it is amusing to hear them talk of their "marchandises mortes." One company had established a series of relays and reservoirs, into which the leeches were deposited, refreshed, and again put in motion; as the journey for a great distance, without such refreshment, usually proves fatal. The steam navigation on the Danube has been of incalculable benefit to Servia; it renders the principality accessible to the rest of Europe, and Europe easily accessible to Servia. The steam navigation of the Save has likewise given a degree of animation to these lower regions, which was little dreamt of a few years ago. The Save is the greatest of all the tributaries of the Danube, and is uninterruptedly navigable for steamers a distance of two hundred miles. This river is the natural canal for the connexion of Servia and the Banat with the Adriatic. It also offers to our summer tourists, on the completion of the Lombard-Venetian railway, an entirely new and agreeable route to the East. By railroad, from Milan to Venice; by steamer from thence to Trieste; by land to Sissek; and the rest of the way by the rapid descent of the Save and the Danube. By the latter route very few turnings and windings are necessary; for a straight line drawn from Milan to Kustendji on the Black Sea, the point of embarkation for Constantinople, almost touches Venice, Trieste, Belgrade, and the Danube. CHAPTER XXXIII. The Foreign Agents. So much for the native government. The foreign agents in Belgrade are few in number. The most prominent individual during my stay there was Baron Lieven, a Russian general, who had been sent there on a special mission by the emperor, to steer the policy of Russia out of the shoals of the Servian question.