Moses Charas studied vipers very closely, and wrote a treatise on their use in medicine (1669) which had a great reputation. He adopted the curious view of Van Helmont that the poison of the viper, which was supposed to be contained in the animal’s saliva, was not there normally, but was created as the effect of rage and terror. According to Charas, the head of the viper, grilled and eaten, would cure its bite, or hung to the neck would cure quinsy. The brain similarly hung on the neck of an infant would greatly assist in cutting the teeth. The skin fastened round the right thigh of a woman was an excellent aid to delivery in childbirth; if given to dogs, cooked or raw, it would cure mange. The fat was a valuable application in gout, or for tumours. Those treatments he had verified by his own experience. Other virtues attributed to vipers were mentioned, but he had not proved them, and could not conscientiously guarantee their existence. One was that the person who swallowed the liver of a viper could not be bitten by any kind of serpent during the ensuing six months. Madame de Sévigné, was a firm believer in the medicinal value of vipers. Writing to her daughter in 1679 she says: “Madame de Lafayette is taking viper broth, which much strengthens her eyesight.” In 1685 she informs her son: “It is to vipers I am indebted for the abundant health I now enjoy. They temper, purify, and refresh the blood. But it is essential to have the vipers themselves, and not the powder, which is heating unless taken in broth, boiled cream, or something refreshing.” Then she goes on to advise him to get M. de Boissy to send him ten dozen vipers from Poitou in a case divided into three or four compartments lined with hay and moss, so that they can be kept at their ease. He is to take two every morning. The heads are to be cut off, the bodies to be scalded and cut into small pieces, and used to stuff a fowl. He is to continue this treatment for a month. The early London Pharmacopœias gave the following form for the Trochisci Viperum required in the preparation of Theriaca: Remove the skin, entrails, head, fat and tail, and boil the flesh of vipers in 8 oz. of water with dill and a little salt, add 2 oz. of white bread twice toasted, ground and sifted, and make into troches, your hands being anointed with opobalsamum or expressed oil of nutmeg. Dry them on a sieve turned bottom upwards in an open place. Turn them frequently until they are quite dry, and keep them in a well-stopped glass or glazed vessel. They will keep good for a year, but it is better to make the treacle with them as soon after they are made as possible.