Use of the word experimentum.
The word employed most of the time by Pliny to denote experience is experimentum.[158] In many passages the word does not indicate anything like a purposive, prearranged, scientific experiment in our sense of that word, but simply the ordinary experience of daily life.[159] We are also told what experti,[160] or men of experience, advise. In a number of passages, however, experimentum is used in a sense somewhat more closely approaching our “experiment.” These are cases where something is being tested. For instance, a method of determining whether an egg is fresh or rotten by putting it in water and watching if it floats or sinks is called an experimentum.[161] That horses would whinny at no other painting of a horse than that by Apelles is spoken of as illius experimentum artis, a test of, or testimony to, his art.[162] The expression religionis experimento is applied to a religious test or ordeal by which the virginity of Claudia was vindicated.[163] The word is also used of ways of telling if unguents are good[164] and if wine is beginning to turn;[165] and of various tests of the genuineness of drugs, gems, earths, and metals.[166] It is also twice used of letting down a lighted lamp into a huge wine cask or into wells to discover if there is danger at the bottom from noxious vapors.[167] If the lamp was extinguished, it was a sign of peril to human life. Pliny further suggests purposive experimentation in speaking of experimenta to discover water under ground[168] and in grafting trees.[169]
Experiments due to scientific curiosity.
Most of the tests and experiences thus far mentioned have been practical operations connected with husbandry and industry. But Pliny recounts one or two others which seem to have been dictated solely by scientific curiosity. He classifies the following as experimenta:[170] the sinking of a well to prove by its complete illumination that the sun casts no shadow at noon of the summer solstice; the marking of a dolphin’s tail in order to throw some light upon its length of life, should it ever be captured again, as it was three hundred years later—perhaps the experiment of longest duration on record;[171] and the casting of a man into a pit of serpents at Rome to determine if he was really immune from their stings.[172]
Medical experimentation.
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.
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.
Marvels proved by experience.
Pliny represents a number of marvelous and to us incredible things as proved by experience. Divination from thunder, for instance, is supported by innumerable experiences, public and private. In two passages out of the three mentioning experti which I cited above, those experienced persons recommended a decidedly magical sort of procedure.[186] In another passage “the experience of many” supports “a strange observance” in plucking a bud.[187] A fourth bit of magical procedure is called “marvelous but easily tested.”[188] Thus the transition is an easy one from signs of experimental science in the Natural History to our next topic, Pliny’s account of magic.