The importance of the human operator as a factor in the performance of marvels, be they medical or magical, is attested by the frequent injunctions of chastity, virginity, nudity, or a state of fasting upon persons concerned in Pliny’s procedure. Sometimes they are not to glance behind them, sometimes they are to speak to no one during the operation. Pliny also mentions men who have a special capacity for wonder-working, such as Pyrrhus, the touch of whose toe had healing power,[353] those whose eyes exert strong fascination, whole tribes of serpent-charmers and venom-curers, and others whose mere presence addles the eggs beneath a setting hen.[354] The power of words spoken by men will be considered separately under the head of incantations. [Sidenote: Absence of medical compounds.] While Pliny attributes the most extreme medicinal virtues to simples, he excludes from his _Natural History_ the strange and elaborate compounds which were nevertheless so popular in the pharmacy of his age. Of one simple, _laser_, he says that it would be an immense task to attempt to list all the uses that it is supposed to have in compounds.[355] His position is that the simple remedies alone are the direct work of nature, while the mixtures, tablets, pills, plasters, washes are artificial inventions of the apothecaries. Once when he describes a compound called “Hermesias” which aids in the generation of good and beautiful children, it seems to be borrowed by Democritus from the _magi_.[356] Furthermore, Pliny thinks that health can be sufficiently preserved or restored by nature’s simple remedies. Compounds are the invention of human conjecture, avarice, and impudence. Such conjecture is often false, not sufficiently taking into account the natural sympathies and antipathies of the numerous ingredients. Often compounds are inexplicable. Pliny also deplores resort to imported drugs from India, Arabia, and the Red Sea, when there are homely remedies at hand for the poorest man.[357] [Sidenote: Sympathetic magic.] We have just heard Pliny refer to the sympathies and antipathies of natural simples, and he often explains the marvelous effects of natural objects upon one another by this relation of love and hatred, friendship or repugnance, discord or concord which exists between them, which the Greeks call sympathy or antipathy, and which Heracleitus was perhaps the first philosopher to insist upon.[358] Some modern students of magic have tried to account for all magic on this theory, and Pliny states that medicine and medicines originated from it.[359] [Sidenote: Antipathies between animals.]