Such was the state of medical knowledge in ancient times, wholly concealed as it was in the language of the Greeks. But the main reason why the medicinal properties of most plants remain still unknown, is the fact that they have been tested solely by rustics and illiterate people, such being the only class of persons that live in the midst of them: in addition to which, so vast is the multitude of medical men always at hand, that the public are careless of making any enquiries about them. Indeed, many of those plants, the medicinal properties of which have been discovered, are still destitute of names—such, for instance, as the one which we mentioned[531] when speaking of the cultivation of grain, and which we know for certain will have the effect of keeping birds away from the crops, if buried at the four corners of the field. But the most disgraceful cause of all, why so few simples are known, is the fact that those even who are acquainted with them are unwilling to impart their knowledge; as though, forsooth, they should lose for ever anything that they might think fit to communicate to others! Added to all this, there is no well-ascertained method to guide us to the acquisition of this kind of knowledge; for, as to the discoveries that have been made already, they have been due, some of them, to mere accident, and others again, to say the truth, to the interposition of the Deity. Down to our own times, the bite of the mad dog, the symptoms of which are a dread of water and an aversion to every kind of beverage, was incurable;[532] and it was only recently that the mother of a soldier who was serving in the prætorian guard, received a warning in a dream, to send her son the root of the wild rose, known as the cynorrhodos,[533] a plant the beauty of which had attracted her attention in a shrubbery the day before, and to request him to drink the extract of it. The army was then serving in Lacetania, the part of Spain which lies nearest to Italy; and it so happened that the soldier, having been bitten by a dog, was just beginning to manifest a horror of water when his mother’s letter reached him, in which she entreated him to obey the words of this divine warning. He accordingly complied with her request, and, against all hope or expectation, his life was saved; a result[534] which has been experienced by all who have since availed themselves of the same resource. Before this, the cynorrhodos had been only recommended by writers for one medicinal purpose; the spongy excrescences, they say, which grow[535] in the midst of its thorns, reduced to ashes and mixed with honey, will make the hair grow again when it has been lost by alopecy. I know too, for a fact, that in the same province there was lately discovered in the land belonging to a person with whom I was staying, a stalked plant, the name given to which was dracunculus.[536] This plant, about an inch in thickness, and spotted with various colours, like a viper’s skin, was generally