The Chemical Era of Anæsthetics
Priestley’s discoveries
The discoveries of Priestley about 1767 led up to the plan of administering gases and vapours of definite composition by inhalation through the lungs, and directly he had demonstrated the existence of “vital air,” or oxygen, the properties of this body were tested in the hope of great results in the art of medicine. Priestley’s experiments concerning the inhalation of oxygen were in time followed by those of Beddoes, who recommended the inhalation of oxygen, hydrogen and other gases in the treatment of disease. It seemed only natural that experiments with other gases and vapours by inhalation should follow. Pearson, of Birmingham, administered ether in this way in 1795 for the relief of consumption, and ten years afterwards Warren, of Boscombe, employed ethereal inhalation to relieve the sufferings attending the later stages of phthisis.
Joseph Priestley
Priestley’s discoveries of the method of liberating and collecting gases, and his demonstrations that certain gases could be absorbed and compressed in water, led to the introduction of aërated waters—carbonic acid gas being the first to be employed.
In the course of time, nitrous oxide, which had been discovered by Priestley in 1776, was compressed in water, and came into general use as a medicinal agent.
Anæsthetic properties of nitrous oxide
In 1798, a Medical Pneumatic Institution was established at Bristol by the exertions of Beddoes and others, and Humphry Davy was appointed superintendent. It was here that he commenced and carried on his notable researches on nitrous oxide. In one of his experiments he constructed a box or chamber in which he inhaled the gas in measured quantities. One day, in the year 1799, when suffering from toothache or inflammation of the gums, he resorted to the inhalation of the gas, and discovered to his great delight that it relieved the pain, which led him to the conclusion he expresses in the following words in “Researches Chemical and Philosophical,” 1800: “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.”
Sir Humphry Davy
Faraday points out similarity in the effects of nitrous oxide and sulphuric ether
About 1806, Woolcombe, of Plymouth, prescribed for Lady Martin, a patient suffering from asthma, the inhalation of sulphuric ether to relieve the attacks. Lady Martin found the inhalation gradually caused her to become unconscious, from which state she would recover in a short time, with the result that the paroxysm of dyspnœa had disappeared. But the teaching of this case, and even the more explicit account of Humphry Davy, was overlooked; and no further development occurred until the year 1818, when Faraday pointed out, in “The Quarterly Journal of Science and Arts,” that the inhalation of the vapour of sulphuric ether produced effects similar to those caused by nitrous oxide.
Michael Faraday
About this time Professor Thompson, of Glasgow, was accustomed annually to amuse his students by allowing them to inhale ether and nitrous oxide until they were intoxicated, and occasionally became unconscious, when it was noticed that they were insensible to the prick of a pin, or a blow. In these cases the gas or ether was inhaled from a bladder. Two drachms of rectified and washed ether were poured into a bladder and allowed to diffuse. Then the mixture of air and ether vapour was breathed, the expired air being allowed to enter the bladder also. Curiously enough, very little improvement has been made on this method of administration to the present day.
On the brink of the discovery
It is an extraordinary fact that, even in the face of such experiments as those we have referred to, no one among the investigators who stood at this time on the brink of so great a discovery ventured over the threshold. It is almost inconceivable in these days to realise, that for thirty-nine years these substances were used for experimental purposes, and even for amusement, without a realisation of the great blessing to humanity that lay almost within grasp. The things that are apparently most plain may lie longest buried; so with the discovery of efficient anæsthesia, which even then developed in an indirect manner.