Oysters are all the better for travelling and being removed to new waters; thus, for example, the oysters of Brundisium, it is thought, when fed in the waters of Avernus, both retain their own native juices and acquire the flavor of those of Lake Lucrinus. Mucianus, who is really a connoisseur, says:—“The oysters of Cyzicus are larger than those of Lake Lucrinus, fresher than those of the British coasts,[160] sweeter than those of Medulæ, more tasty than those of Ephesus, more plump than those of Lucas, less slimy than those of Coryphas, more delicate than those of Istria, and whiter than those of Circeii.” For all this, however, it is a fact well ascertained that there are no oysters fresher or more delicate than those of Circeii, last mentioned. According to the historians of the expedition of Alexander, there were oysters found in the Indian Sea a foot in diameter:[161] among ourselves, too, the nomenclature of some spendthrift and gourmand has found for certain oysters the name of “tridacna,”[162] wishing it to be understood thereby, that they are so large as to require three bites in eating them. We will take the present opportunity of stating all the medicinal properties that are attributed to oysters. They are singularly refreshing[163] to the stomach, and tend to restore the appetite. Luxury, too, has imparted to them an additional coolness by burying them in snow, thus making a medley of the produce of the tops of mountains and the bottom of the sea. Calcined oyster-shells, mixed with honey, are good sprinkled upon burns, and are highly esteemed as a dentifrice. Book VII. THE NATURAL HISTORY OF BIRDS. CHAPTER I. THE OSTRICH. The history of birds follows next, the very largest of which, and indeed almost approaching to the nature of quadrupeds, is the ostrich of Africa or Æthiopia. This bird exceeds in height a man sitting on horseback, and can surpass him in swiftness, as wings have been given to aid it in running; in other respects ostriches cannot be considered as birds, and do not raise themselves from the earth. They have cloven talons, very similar to the hoof of the stag; with these they fight, and they also employ them in seizing stones for the purpose of throwing at those who pursue them.[164] They have the marvellous property of being able to digest every substance without distinction, but their stupidity is no less remarkable; for although the rest of their body is so large, they imagine, when they have thrust their head and neck into a bush, that the whole of the body is concealed. Their eggs are prized on account of their large size, and are employed as vessels for certain purposes, while the feathers of the wing and tail are used as ornaments for the crest and helmet of the warrior. CHAPTER II. THE PHŒNIX.