for it is said that there are not more than three thousand families which have a right to claim that privilege, by virtue of hereditary succession; and that for this reason those persons are called sacred, and are not allowed, while pruning the trees or gathering the harvest, to receive any pollution, either by intercourse with women, or coming in contact with the dead; by these religious observances it is that the price of the commodity is so considerably enhanced. Some persons, however, say, that the right of gathering incense in the forests belongs to all these people in common, while others again state, that they take their turns year by year. CHAP. 31.—THE TREES THAT BEAR FRANKINCENSE. Nor is it by any means agreed what is the appearance of the incense-tree. We have sent several expeditions against Arabia, and the Roman arms have penetrated into the greater part of that country; indeed, Caius Cæsar,[513] the son of Augustus, even earned considerable renown there; and yet this tree has been described by no Latin writer, at least that I know of. The descriptions given of it by the Greek writers vary very considerably: some of them say that it has exactly the leaf of the pear-tree, only somewhat smaller, and of a grass-green colour. Others, again, say, that it has a rather reddish leaf, like that of the mastich, and others, that it is a kind of terebinth,[514] and that King Antigonus, to whom a branch of it was brought, was of that opinion. King Juba, in the work which he wrote and dedicated to Caius Cæsar, the son of Augustus, who was inflamed by the wide-spread renown of Arabia, states, that the tree has a spiral stem, and that the branches bear a considerable resemblance to those of the Pontic maple, while it secretes a sort of juice very similar to that of the almond-tree. Such, he says, is the appearance of the tree as seen in Carmania and Egypt, where it was introduced and planted under the auspices of the Ptolemies when reigning there. It is well known that it has a bark not unlike that of the laurel, and, indeed, some persons have asserted that their leaves are similar. At all events, such was the case with the tree as it grew at Sardes: for the kings of Asia also took considerable care to have it planted there. The ambassadors who in my time have come to Rome from Arabia, have made all these matters more uncertain, even, than they were before; a thing at which we may justly be surprised, seeing that some sprigs even of the incense-tree have been brought among us, from which we have some reason to conclude that the parent tree is round and tapering, and that it puts forth its shoots from a trunk that is entirely free from knots. CHAP. 32.—VARIOUS KINDS OF FRANKINCENSE.