In another passage of the _Guide_ Maimonides cautions, however, against the abuse of divine names, and, while he holds to the Tetragrammaton “which is written but is not pronounced as it is spelled,” deplores the many inventions of meaningless and inefficacious names which superstitious and insane men have too often imposed upon the credulity of good men as possessed of peculiar sanctity and purity and having the virtue of working miracles. He therefore warns his readers against such “amulets or experimental charts.”[638] [Sidenote: Occult virtue and empirical remedies in his work on poisons.] Maimonides again approves of empirical remedies and of occult virtues in his treatise on poisons. He holds that counter-poisons do not act by any physical or chemical quality but by their entire substance or by a special property.[639] Lemon pips, peeled and applied in a compress; a powdered emerald, which should be a beautiful green, quite transparent, and of good water; and the animal bezoar, which comes from the eyes or gall bladder of deer; these are antidotes whose efficacy is proved by incontestible experimentation. When _terra sigillata_ cannot be had, a powdered emerald of the sort just described may be substituted for it as an ingredient in the grand theriac.[640] Maimonides believes that this last named remedy is the outcome of experiments with vipers carried on through the course of centuries by ancient philosophers and physicians.[641] As for the stone _bezoar_, the writings of the moderns are full of marvelous tales concerning it, but Galen does not mention it, and Maimonides has tried all the varieties which he could obtain against scorpion bites without the least success. But experience confirms the virtue of the _bezoar_ of animal origin, as has been stated. Maimonides’ observations concerning cures for the bites of mad dogs are interesting. He states that at first the bite of a mad dog does not feel any different from that of a dog who is not mad. He also warns his readers not to trust to books to distinguish between the two, but unless they are sure that the dog was not mad, to keep on the safe side by taking the remedies against the bite of a mad dog.[642] He also states that all of the various remedies listed for the cure of the bite of a mad dog must be employed before hydrophobia manifests itself, “for after the appearance of that symptom, I have never seen a patient survive.”[643] In speaking of sucking the venom from a wound, Maimonides affirms that it is better to have this done by a fasting person, since the spittle of such a person is itself hostile to poisons.[644] [Sidenote: Attitude to astrology.]