Very different were the feelings by which the Roman generals and people were swayed even in their most civilized times and at the height of their unequalled power. Through all the gloss which history has thrown over the character of these masters of the universe there appears a spirit of unreclaimed barbarity which was never entirely shaken off. From the scenes of their distant conquests their prætors sent to the metropolis of the world bears and lions and leopards and tigers; but a love of science had no share in the motives for the gratification of which they were transmitted, and the chief curiosity manifested on such occasions by the people of Rome was to ascertain how speedily hundreds or thousands, as the case might happen, of these ferocious beasts would destroy each other when turned out half-famished into the public amphitheatre, or how long a band of African slaves, of condemned criminals, or of hired gladiators, would be able to maintain the unequal contest against them. The consul or emperor who exhibited at one time the greatest number of animals to be thus tortured before the eyes of equally brutal spectators was held in the highest esteem among a people who regarded themselves as civilized, and whose chief delight was in witnessing these wanton effusions of blood. It was only under the later Cæsars that a few private individuals brought together in their _vivaria_ a considerable number of rare and curious animals; and the Natural History of Pliny derives most of its zoological value from the opportunities which he had of consulting these collections. But the monstrous fables and the innumerable errors, which the most superficial examination would have taught him to correct, with which every page of this vast compilation absolutely teems, speak volumes with regard to the wretched state of natural science in the most splendid days of Roman greatness.