_Experimentum_ is employed by Pliny in a medical sense which becomes very common in the middle ages. He calls some remedies for toothache and inflamed eyes _certa experimenta_—sure experiences.[173] Later _experimentum_ came to be applied to almost any recipe or remedy. Pliny, indeed, speaks of the doctors as learning at our risk and getting experience through our deaths.[174] In another passage he states more favorably that “there is no end to experimenting with everything so that even poisons are forced to cure us.”[175] He also briefly mentions the medical sect of Empirics, of whom we shall hear more from Galen. He says that they so name themselves from experiences[176] and originated at Agrigentum in Sicily under Acron and Empedocles. [Sidenote: Chance experience and divine revelation.] Pliny is puzzled how some things which he finds stated in “authors famous for wisdom” were ever learned by experience, for example, that the star-fish has such fiery fervor that it burns everything in the sea which it touches, and digests its food instantly.[177] That adamant can be broken only by goat’s blood he thinks must have been divinely revealed, for it would hardly have been discovered by chance, and he cannot imagine that anyone would ever have thought of testing a substance of immense value in a fluid of one of the foulest of animals.[178] In several other passages he suggests chance, accident, dreams,[179] or divine revelation as the ways in which the medicinal virtues of certain simples were discovered. Recently, for example, it was discovered that the root of the wild rose is a remedy for hydrophobia by the mother of a soldier in the praetorian guard, who was warned in a dream to send her son this root, which cured him and many others who have tried it since.[180] And a soldier in Pompey’s time accidentally discovered a cure for elephantiasis when he hid his face for shame in some wild mint leaves.[181] Another herb was accidentally found to be a cure for disorders of the spleen when the entrails of a sacrificial victim happened to be thrown on it and it entirely consumed the milt.[182] The healing properties of vinegar for the sting of the asp were discovered by chance in this wise. A man who was stung by an asp while carrying a leather bottle of vinegar noticed that he felt the sting only when he set the bottle down.[183] He therefore decided to try the effects of a drink of the liquid and was thereby fully cured.[184] Other remedies are learned through the experience of rustics and illiterate persons, and yet others may be discovered by observing animals who cure their ills by them.[185] Pliny’s opinion is that the animals have hit upon them by chance. [Sidenote: Marvels proved by experience.]