This is the exact position in which the master desires them to place his runaway slave--"tree him," and then set up a howl that soon brings up the hunters. They are never set upon the slaves to bite or injure them, but only placed upon their track to follow and hunt them. So perfect of scent are these animals, that the master, when he is about to pursue a runaway, will find some clothing, however slight, which the missing slave has left behind him, and giving it to the hounds to smell, can then rely upon them to follow the slave through whole plantations of his class, none of whom they will molest, but, with their noses to the ground, will lead straight to the woods, or wherever the slave has sought shelter. On the plantations these dogs are always kept chained when not in actual use, the negroes not being permitted to feed or to play with them; they are scrupulously fed by the overseer or master, and thus constitute the animal police of the plantation. In no wise can they be brought to attack a white man, and it would be difficult for such to provoke them to an expression of rage or anger, while their early and systematic training makes them feel a natural enmity to the blacks, which is of course most heartily reciprocated. Cuba has been called the hot-bed of slavery; and it is in a certain sense true. The largest plantations own from three to five hundred negroes, which establishments require immense investments of capital successfully to manage. A slave, when first landed, is worth, if sound, from four to five hundred dollars, and more as he becomes acclimated and instructed, their dull natures requiring a vast deal of watchful training before they can be brought to any positive usefulness, in doing which the overseers have found kindness go a vast deal farther than roughness. Trifling rewards, repaying the first efforts at breaking in of the newly imported negro, establishes a good understanding at once, and thus they soon grow very tractable, though they do not for a long time understand a single word of Spanish that is addressed to them.