I had scarcely any hope of the patient in St. George’s Hospital from the very commencement of the accident; for I felt that if he could be recovered by artificial respiration, his own breathing would have remedied the accident, even before it was discovered. From what has been published respecting the pulse sometimes stopping and commencing again, during the inhalation of chloroform, it is probable that many accidents, in which the heart has been nearly paralysed, have happened, and rectified themselves, without attracting much notice.
I have no doubt that in each of these accidents the patient must have taken into his lungs at one moment air containing upwards of thirty per cent. of vapour of amylene. And there is no doubt that the cause of this was the unsteady boiling point of the agent. If the amylene with which I was supplied had boiled steadily at the same temperature, there is no doubt that the means which I was employing, and which had enabled me for ten years, whilst exhibiting chloroform, to give four per cent. of the vapour, probably without ever allowing the quantity to exceed six per cent., would have enabled me to give fifteen per cent. of vapour of amylene without permitting the quantity to exceed twenty per cent.
The alteration in the boiling point of a specimen of amylene from 86° to 115° Fah. would cause it to give off more than twice as much vapour in the beginning of its evaporation as towards the end; and, moreover, the different specimens of it did not always possess the same amount of volatility.
The temperature of the external air as it influenced that of the water-bath of the inhaler would have some influence over the evaporation of the amylene, but I altered the amount of evaporating surface of paper according to the season of the year for amylene, as I was in the habit of doing for chloroform. The highest temperature of April 7, the day on which the first accident happened, was at Greenwich, according to the Report of the Astronomer Royal, 62°; and on July 30, the day on which the second accident happened, was 78·7°. After the first accident, I had reduced the surface of bibulous paper in the inhaler to one-half of what it had previously been.
The first of the above accidents happened in the 144th case in which I administered amylene, and the second in the 238th case. In the ninety cases and upwards in which I administered amylene between these two accidents, I never had occasion to feel a moment’s uneasiness about it.
In the future cases in which I employ amylene, it is my intention to administer it from a bag or balloon, putting in so much of the liquid as will make fifteen per cent. of vapour when the bag is filled up with air. In this manner, the variability in the boiling point of the amylene can have no influence whatever on the amount of vapour which the patient breathes; and if the vapour be breathed over again, within certain limits, in the manner of nitrous oxide gas, there will be a great saving in the amount of amylene consumed.
In my first paper on amylene, which was read on January 10th, 1857, I said: “While I cannot venture to predict for it the absolute safety which seems to attend sulphuric ether under all circumstances, I trust that it will be perfectly safe with careful management”[[177]] And I added further on, “It is my opinion that the cold produced during its evaporation would, in all the ordinary methods of inhalation, prevent the air from taking up a quantity of the vapour which would be dangerous.”
Although amylene was largely used in Paris, Strasbourg, Montpelier, and Lyons, soon after I published my first account of it, and although I have lately heard that it is still employed in Paris and Berlin, nearly eighteen months after its first use in these places, I am happy that I have not heard of any accident from its use except the two which happened in my own hands.
M. Giraldis, of Paris, who was present at the operating theatre of St. George’s Hospital when the accident happened at that institution, had already employed amylene in 100 cases in children, and I believe that he continues to use it. Given on a handkerchief or sponge, I believe that amylene is safer than chloroform, owing to the greater cold produced during its evaporation, and the limit thereby put to the amount of vapour which is given off; but I have seldom given it in this manner, as I do not think it would be certain and regular in its action, and any doubt on these points would, with me, have quite overbalanced its other advantages. In applying amylene on a sponge, M. Rigaud of Strasbourg used 100 grammes (between four and five fluid ounces) in making an adult patient insensible, although half a fluid ounce suffices with the inhaler I employed.
Mr. Clarke, of Bristol, in a paper which he published on amylene,[[178]] says: “It seemed impossible to get too much into the system, and with this I have been greatly impressed; it is this fact that appears to me to promise an immunity from danger.... It requires to be given almost unintermittingly, and requires the same amount of attention to keep up its effects as chloroform does to keep the patient safe. The direction of the attention, however, is one less calculated to give anxiety.”