Part 33

I performed some experiments in 1848, for ascertaining the proportions of vapour of ether present in the blood in the different degrees of narcotism. They were conducted on the same principles as those previously related, which were performed for the purpose of determining the same point in regard to chloroform.

Experiment 31. Two grains of ether were put into a jar holding 200 cubic inches, and the vapour diffused equally, when a tame mouse was introduced, and allowed to remain a quarter of an hour, but it was not appreciably affected.

Experiment 32. Another mouse was placed in the same jar, with three grains of ether, being a grain and a half to each 100 cubic inches. In a minute and a half, it was unable to stand, but continued to move its limbs occasionally. It remained eight minutes without becoming further affected. When taken out, it was sensible to pinching, but fell over on its side in attempting to walk. In a minute and a half, the effect of the ether appeared to have gone off entirely.

Experiment 33. A white mouse in the same jar, with four grains of ether, was unable to stand at the end of a minute, and at the end of another minute ceased to move, but continued to breathe naturally, and was taken out at the end of five minutes. It moved on being pinched, began to attempt to walk at the end of a minute, and in two minutes more seemed quite recovered.

Experiment 34. Five grains of ether, being two and a half grains to each 100 cubic inches, were diffused throughout the same jar, and a mouse put in. It became rather more quickly insensible than the one in the last experiment. It was allowed to remain eight minutes. It moved its foot a very little when pinched, and recovered in the course of four minutes.

Experiment 35. A white mouse was placed in the same jar with six grains of ether. In a minute and a half, it was lying insensible. At the end of three minutes, the breathing became laborious, and accompanied by a kind of stertor. It continued in this state till taken out, at the end of seven minutes, when it was found to be totally insensible to pinching. The breathing improved at the end of a minute; it began to move at the end of three minutes; and five minutes after its removal, it had recovered.

Experiment 36. The same mouse was put into this jar on the following day, with seven grains of ether, being 3·5 grains to the 100 cubic inches. Stertorous breathing came on sooner than before; it seemed at the point of death when four minutes had elapsed; and being then taken out, was longer in recovering than after the last experiment.

Experiment 37. Two or three days afterwards, the same mouse was placed in the jar, with eight grains of ether, being four grains for each 100 cubic inches. It became insensible in half a minute. In two minutes and a half, the breathing became difficult; and at a little more than three minutes, it appeared that the breathing was about to cease, and the mouse was taken out. In a minute or two, the breathing improved; and in the course of five minutes from its removal, it had recovered.

The temperature of the mice employed in the above experiments was about 100°. That of the birds in the following experiments was higher, as is stated; and they differ widely from the mice in the strength of vapour required to produce a given effect, although I found but little difference between the mice and birds, in this respect, in the former experiments on chloroform. And one of the linnets was employed in both sets of experiments. Having seen MM. Dumeril and Demarquay’s statement of the diminution of animal temperature from inhalation of ether and chloroform, before the following experiments were performed, the thermometer was applied at the beginning and conclusion of some of them. I have selected every fourth experiment from a larger series on birds.

Experiment 38. 18·4 grains of ether were diffused through a jar holding 920 cubic inches, being two grains to each 100 cubic inches, and a green linnet was introduced. After two or three minutes it staggered somewhat, and in a few minutes more appeared so drowsy, that it had a difficulty in holding up its head. It was taken out at the end of a quarter of an hour, quite sensible, and in a minute or two, was able to get on its perch. The temperature under the wing was 110° before the experiment began, and the same at the conclusion.

Experiment 39. Another linnet was placed in the same jar, with four grains of ether to each 100 cubic inches of air. In two minutes it was unable to stand, and in a minute more, voluntary motion had ceased. It lay breathing quietly till taken out, at the end of a quarter of an hour. It moved its foot slightly when it was pinched. In three minutes it began to recover voluntary motion, and was soon well. The temperature was 110° under the wing, when put into the jar, and 105° when taken out.

Experiment 40. A green linnet was put into the same jar with 55·2 grains of ether, being six grains to 100 cubic inches. It was insensible in a minute and a half, and lay motionless, breathing naturally, till taken out at the end of a quarter of an hour. It moved its toes very slightly when they were pinched with the forceps, and it began to recover voluntary motion in two or three minutes. Temperature 110° before the experiment, and 102° at the end.

Experiment 41. A linnet was placed in the same jar, containing eight grains of ether to each 100 cubic inches. Voluntary motion ceased at the end of a minute. The breathing was natural for some time, but afterwards became feeble, and at the end of four minutes appeared to have ceased; and the bird was taken out, when it was found to be breathing very gently. It was totally insensible to pinching. The breathing improved, and it recovered in four minutes.

Experiment 42. 9·2 grains of ether, being one grain to each 100 cubic inches of air, were diffused through the jar, holding 920 cubic inches of air, and a frog was introduced. At the end of a quarter of an hour, it had ceased to move spontaneously, but could be made to move its limbs, by inclining the jar so as to turn it over. At the end of half an hour, voluntary motion could no longer be excited, and the breathing was slow. It was removed, at the end of three-quarters of an hour, quite insensible, and the respiratory movements being performed only at long intervals, but the heart beating naturally; and it recovered in the course of half an hour. The temperature of the room was 55° at the time of this experiment.

We find from the 32nd experiment, that a grain and a half of ether for each 100 cubic inches of air, is sufficient to induce the second degree of narcotism in the mouse; and a grain and a half of ether make 1·9 cubic inch of vapour, of specific gravity 2·586. Now the ether I employed boiled at 96°. At this temperature, consequently, its vapour would exclude the air entirely; and ether vapour, in contact with the liquid giving it off, could only be raised to 100° by such a pressure as would cause the boiling point of the ether to rise to that temperature. That pressure would be equal to 32·4 inches of mercury, or 2·4 inches above the usual barometrical pressure; and the vapour would be condensed somewhat, so that the space of 100 cubic inches would contain what would be equivalent to 108 cubic inches at the usual pressure. This is the quantity, then, with which we have to compare 1·9 cubic inch, in order to ascertain the degree of saturation of the space in the air-cells of the lungs, and also of the blood; and by calculation, as when treating of chloroform,

1·9 is to 108 as 0·0175 is to 1.

So that we find 0·0175, or 1–57th to be the amount of saturation of the blood by ether necessary to produce the second degree of narcotism; and as by Experiment 35, three grains in 100 cubic inches produced the fourth degree of narcotism, we get 0·035, or 1–28th, as the amount of saturation of the blood in this degree. Now this is within the smallest fraction of what was found to be the extent of saturation of the blood by chloroform, requisite to produce narcotism to the same degrees. But the respective amount of the two medicines in the blood differs widely; for whilst chloroform required about 288 parts of serum to dissolve it, I find that 100 parts of serum dissolve five parts of ether at 100°; consequently 0·05 × 0·0175 gives 0·000875, or one part in 1142, as the proportion in the blood in the second degree of narcotism; and 0·05 × 0·035 gives 0·00175, or one part in 572, as the proportion in the fourth degree.

In Experiment 42 the frog was rendered completely insensible by vapour of a strength which was not sufficient to produce any appreciable effect on the mouse in Experiment 31. This is in accordance with what was met with in the experiments with chloroform. Air, when saturated with ether at 55°, contains 32 grains in each 100 cubic inches; so that the blood of the frog might contain 1–32nd part as much as it would dissolve, which, although not quite so great a proportion as was considered the average for the fourth degree of narcotism in the mice, yet was more than sufficient to render insensible the mouse in Experiment 34.

There is a remarkable difference between the birds and the mice, in respect to the proportions of ether and air required to render them insensible, a difference that was not observed with respect to chloroform. In some experiments with ether on guineapigs, which are not adduced, they were found to agree with mice in the effects of various quantities.

The birds were found to require nearly twice as much; five grains to 100 cubic inches, the quantity used in an experiment between the thirty-ninth and fortieth, which is not related, may be taken as the average for the fourth degree of narcotism in these birds, with a temperature of 110°. By the kind of calculation made before, we should get a higher amount of saturation of the blood than for the same degree in mice. But as serum at 110° dissolves much less ether than at 100°, the quantity of this medicine in the blood of birds is not greater than in that of other animals; and, considered in relation to what the blood would dissolve at 100°, the degree of saturation is the same.

By Experiments 36, 37, and 41, we find that with ether, as with chloroform, a quantity of vapour in the air, somewhat greater than suffices to induce complete narcotism, has the effect of arresting the respiratory movements.

In treating of chloroform (page 74), the average quantity of serum in the adult human subject was estimated at 410 fluidounces. In order to find the quantity of ether in the system, we may multiply 410 by 0·000875 for the second degree of narcotism, and by 0·00175 for the fourth degree, when we shall obtain 0·358 and 0·71 of an ounce, i. e. f. ʒii. ♏︎l in the first instance, and f. ʒv. ♏︎xl in the second. In the third degree of narcotism, in which surgical operations are usually performed, the quantity is intermediate, or a little over four drachms.

On the Administration of Ether. About a fluid ounce of ether is usually inhaled by an adult patient in becoming insensible; fully one-half of this is, however, thrown back from the lungs, windpipe, nostrils, and face-piece, without being absorbed. I usually put two fluid ounces of ether into the inhaler above described, at the beginning of the inhalation, and this quantity often lasts to the end of the operation, if it is not a protracted one. The inhaler is connected, by means of a wide elastic tube, with a face-piece similar to that described and delineated in treating of chloroform. It is necessary that the inhalation should commence, as in the case of chloroform, with the expiratory valve of the face-piece turned on one side, for the admission of air which is not charged with ether, and that the vapour should be admitted to the air-passages by degrees, to avoid the irritation that would arise from suddenly inspiring any considerable quantity of the vapour. The vapour of ether is very much less pungent than an equal quantity of the vapour of chloroform; but as the patient requires to breathe about six times as much of it in the inspired air, it feels quite as pungent as that of chloroform, and, perhaps, a little more so. Whilst the patient never requires to take in more than four or five per cent. of vapour of chloroform in the inspired air, he requires to inhale about thirty per cent. of vapour of ether, in order to be rendered insensible in a convenient time. The air-passages, however, soon get accustomed to the presence of the vapour of ether, and in a minute and a half or two minutes after the patient begins to inhale, he can usually bear the valve to be closed so far as to charge the air with as much vapour as is necessary speedily to cause insensibility. The inhaler yields quite sufficient vapour when the water-bath is at 50° Fahr.; and at the seasons of the year when the temperature of the water is higher, the expiratory valve of the face-piece can be left more or less open to admit a portion of air which has not passed through the inhaler.

I prefer the flavour of ether vapour to that of chloroform; and the sensations I experience from the inhalation of ether are more pleasurable than those from chloroform. Many persons agree with me on both those points; but some prefer chloroform. The quantity of ether expended in causing insensibility is eight or ten times as great as that of chloroform, but the quantity used in a protracted operation is not so disproportionate; for, owing to the great solubility of ether and the large quantity of it which is absorbed, it is much longer in exhaling by the breath, and when the patient is once fairly insensible, it does not require to be repeated so frequently as chloroform.

In administering ether, I usually rendered adult patients insensible in four or five minutes, and children in two or three minutes. A somewhat longer time was occasionally occupied in cases in which the air-passages were irritable, or where there was much rigidity and struggling. I never failed to make the patient insensible in any one instance in which I administered ether. I have notes of 152 cases in which I administered ether, before chloroform was introduced, and twelve cases in which I have exhibited it since.

Nearly all the great operations of surgery were included several times amongst the cases in which I administered ether. Amputation of the thigh was performed in nineteen cases; fifteen of the patients recovered, and four died. Amputation of the leg was performed eleven times; eight of the patients recovered, and three died. The arm was amputated three times; one of the patients died, and two recovered. There were thus thirty-three of the larger amputations with eight deaths, being a mortality of twenty-four per cent. There were two amputations of the forearm, and both patients recovered. There were nine operations of lithotomy; seven of the patients recovered, and two died. Five of the patients were children, who all recovered; the two deaths occurring amongst the four adult patients. Eighteen female patients had the breast removed for tumour, and they all recovered except one.

On July 1st, 1847, Mr. Cutler amputated the leg of a man, aged forty-four, in St. George’s Hospital, who had suffered from disease of the tibia and ankle, which had existed thirty years, and was caused by an accident. This patient died on the seventh day, of sloughing phagedena, which was present in the hospital. It was then found that he had disease of the heart. Its structure was soft and easily lacerable; much fat was mixed up with the muscular structure. The aortic valves were much thickened, and almost cartilaginous in structure. Two of them were so much contracted that they were together about the size of a healthy one. The left ventricle was dilated, and the right ventricle still more so; its walls being extremely thin. The ether had acted quite favourably on this man.

I administered ether repeatedly in infants and old people. Some of the infants were operated on by Mr. George Pollock, in 1847, for congenital cataract by drilling; and two of them were operated on, in 1857, for hare-lip, by Mr. Fergusson and Mr. Bowman. A gentleman, one of whose toes the late Mr. Liston amputated in 1847, was said to be subject to apoplectic attacks. The ether acted very favourably. Amongst the operations which Mr. Liston performed on patients to whom I administered ether, was the tying of the external iliac artery in a man, aged forty, for an aneurism of the groin, situated partly above Poupart’s ligament. The patient lay perfectly still in this, as in all the other important operations in which I administered ether. He recovered.