The Persian Pharmacopœia[25] contains some recipes for fumigation, called bouc-houri, that were inhaled, for the medicines are directed to be made up into balls or cubes which are to be placed on the live coals, and the head is to be held over them. Some of the prescriptions contain myrrh, camphor, mace, and storax, and are for the cure of coryza and catarrh; one containing musk, camphor, guaiacum, etc., is said to comfort the brain and intellect, and to be useful in palpitation of the heart, faintness, and debility of the senses. This Pharmacopœia also contains[26] a “remedium odorativum somniferum”, which consists of opium and camphor, besides the seeds of roses and the root of mandragora. The ingredients are to be powdered and put in a box, for the purpose of being smelt at. There is also[27] a stupifying remedy prepared with five drachms of opium and ten drachms of black poppy, which are directed to be boiled to dryness in water with a pound of wheat, and then powdered. It is added that whoever shall take a drachm and a half of this wheat will be alienated from his senses. With regard to the last but one of the above prescriptions—that to be put in a box for smelling, it may be observed that, as heat was not applied, the only ingredient which would produce any effect is the camphor. The discoveries of Cavendish, Priestley, Lavoisier, and others respecting the nature of atmospheric air and the more important gases, gave an impetus to medicinal inhalations, at the latter part of the last century. Dr. Beddoes, in particular, distinguished himself by the administration of oxygen, hydrogen, carbonic acid, and other gases, in consumption and various diseases. Dr. Richard Pearson exhibited the vapour of ether in consumption with some advantage in the year 1795.[28] Three years afterwards, a medical pneumatic institution was established at Bristol, by the exertions of Dr. Beddoes and others. The celebrated Humphrey Davy was the superintendent. This establishment was not very successful in the immediate objects for which it was instituted, but Davy made at this place his masterly researches concerning nitrous oxide gas. In the course of his experiments, he found that severe pain arising from inflammation of his gums was relieved by breathing this gas, and he published the following opinion:— “As nitrous oxide in its extensive operation seems capable of destroying physical pain, it may probably be used with advantage during surgical operations in which no great effusion of blood takes place.”[29]