OBSERVATIONS AND EXPERIMENTS ON THE DIRECT ACTION OF ETHER ON THE BLOOD
A point which may become of great interest and importance is, whether other agents cannot be combined with the ether; for instance, laudanum where the pains are dangerously violent; or tincture of ergot where they are insufficient. In one of Dr. Simpson's cases, the patient inhaled a volatile solution of ergot. The pains, which had previously been languid, almost immediately became strongly expulsive, and the child was born in a quarter of an hour. The woman had been in labour from forty to
... r from forty to fifty hours. In conclusion, I would state it as my opinion, that with perfectly pure ether, carefully administered by skilful persons, and with good apparatus, and especially by one containing an appendage with a supply of oxygen, the operation not being commenced until efficient etherization is produced, the employment of ether is not only justifiable, but promises to be instrumental in materially diminishing the dangers of operative midwifery. Probably, in natural cases it will be both sufficient and safer to carry the etherization only to the second stage, in which partial consciousness remains, but sensation is abolished; and towards the end, when the pains are ordinarily intolerable, to induce perfect narcotism. From the results which I have already obtained, it is my intention i to continue the use of this valuable agent, and I do not hesitate to state my belief, that future experience will fully con-z ' firm my present opinion. I John-street, Bedford-row, April, 1847. -super-mare. IN the state of uncertainty which at present characterizes the opinion of the profession respecting the propriety of having recourse to the novel employment of ether as a means of suppressing pain during parturition, and the performance of surgical operations, it is hoped that the facts which form the subject. of the following communication may contribute ao divest the question of some of the sources of ambiguity in which it is still involved. The altered condition of the arterial blood, resulting from the inhalation of ether, has been pointed out by several of the French physiologists, who found that a dark and fluid state of the blood was produced in animals subjected to the process termed " etherization," and a similar result has been repeatedly observed by surgeons in this country, whilst operating on patients under the influence of ether, the arterial blood lost during the operation having exhibited the change of character above mentioned. Considering, however, the important influence which the change in question must necessarily exert on the animal economy, it seems surprising that it has not yet been made the subject of more special investigation. It is true that M. Amussat, in his experiments on the lower animals, purposely continued until a fatal result ensued, does not hesitate to ascribe the cause of death to the altered state of the blood, and that Mr. Adams, of the London Hospital, however questionable may be his mode of explaining the rationale of the subject, nevertheless refers the peculiar effect of the ether to its influence primarily on the arterial blood, yet I am not aware that any satisfactory attempt has hitherto been made to ascertain the mode in which the altered state of the blood is brought about,*-whether it is owing solely to the direct action of the ether on the blood; orwhetheritmaynot rather depend-as has, I believe, been suggested-upon the deficiency of the usual amount of oxygen, in consequence of the substitution of a considerable proportion of the vapour of ether, in place of the normal supply of atmospheric air; whether the effect produced is in any way determined or modified by vitality; or whether it is independent of this influence, and occurs equally in blood removed from the body, and is therefore to be regarded as a chemical rather than a vital change. On these, and some similar questions, it has appeared to me desirable that we should have some more certain information than that at present possessed; and it was with a view, in some measure, to supply this desideratum, that I was induced to try the effect of the direct admixture of ether with arterial blood, when removed from the body. For this purpose I collected in two separate two-ounce bottles, some arterial blood, as it was flowing fresh from a * Since the above was written, the observations of M. Rnbin, in relation to this subject, as reported in THE LANCET of April 17th, have come under my notice. The views, however, of M. Robin, and the conclusions he arrives at, appear, as will hereafter be shown, so different from those forming the subject of the present communication; as to render any material alteration of the above remark unnecessary., divided vessel in a sheep. In one of the bottles, a small quantity of pure washed ether* had been previously introduced, whilst the other, being employed merely as a standard óf comparison, contained only atmospheric air, and as soon as each bottle became about half full of blood, it was immediately closed hermetically. On comparing the two bottles after the lapse of two or three minutes, the blood in that containing the ether was found to be almost black, and in some measure fluid, the coagulum formed being at the same time of a much softer consistence than usual. In the second bottle, that in which no ether was introduced, the blood at this time exhibited itself as a firm and uniform coagulum, retaining all its florid arterial character. This experiment, made some weeks since, has subsequently been varied, as opportunity has been afforded, and the following may be taken as a brief summary of the results arrived at. Oxygen gas introduced into the vessel containing ether, does not in any way prevent the peculiar action of the ether on arterial blood, nor does the subsequent transmission of oxygen gas through the darkened etherized blood restore to it either its arterial colour, or the power of coagulating ; though it seems probable that the cause of the failure of the oxygen in displaying its usual agency on the blood in this instance, may be attributable to the presence of some free ether still remaining in the vessel. Ether poured on fresh arterial blood produces the same results as where it is first introduced into the vessel in which the blood is subsequently to be received, and in each instance the effect is increased by agitation of the vessel. Arterial blood collected in a vessel containing ether was found to become darker and more fluid than when collected in a vessel containing carbonic acid gas. The common sulphuric and nitric spirits of ether of the shops, when mixed with arterial blood, produce, apparently, the same effects as are obtained with the washed ether. Of these experiments, which, believing them to be new, I have thought it worth while to communicate, the first appears to be the only one deserving more particular attention. From this experiment alone, the questions formerly proposed will be found, in great measure, to have received their solution, whilst a more attentive consideration of it will assist us in drawing some practical conclusions in reference to the novel use to which ether is now applied. We learn from this experiment that the state of the blood observed in etherized patients does not depend merely upon the absence of the normal amount of oxygen in the lungs, nor upon any impediment which the process of etherization, with the apparatus employed, &c., may offer to the due elimimation and disengagement of the carbonic acid from the lungs; neither does the ether act;as stated by M. Robin, simply by " preventing the transformation of venous into arterial blood," since it is shown, in this experiment, not only " to oppose the arterialization of the blood," for the reasons assigned by M. Robin, but actually to deprive arterial blood of the oxygen already combined with it. The conclusion, therefore, is inevitable, that the change produced in the blood is independent of any vital agency, and hence must be regarded as of a purely chemical nature, dependent, in all probability, on the affinity which ether has for oxygen-a property which the high temperature to which it is exposed when taken into the lungs would have the effect of augmenting in a remarkable degree, so as to favour its rapid absorption of oxygen from the oxygenized constituents of the blood. It seems scarcely necessary to do more than advert to this changed condition of the blood, in order to indicate the true source through which an explanation of the physiological effects of ether must be sought. " Physiology," says Liebig, " has sufficiently decisive grounds for the opinion, that every motion, every manifestation of force, is the result of a transformation of the structure or of its substance ; that every conception, every mental affection, is followed by changes in the chemical nature of the secreted fluids; that every thought, every sensation, is accompanied by a change in the composition of the substance of the brain." And again :—" The change of matter, the manifestation of mechanical force, and : the absorption of oxygen, are, in the animal body, so closely connected with each other, that we may consider the amount of motion, and the quantity of living tissue transformed, as : proportional to the quantity of oxygen'inspired and consumed * Should the use of the liquid ether in these experiments be objected to t as affording no sufficient ground of analogy with the process as ordinarily ! employed, it must be remembered that a similar state of the blood to that ; here described is, in many cases, undoubtedly found to result from the , process of etherization, whilst it is presumed that no very marked differ-L ences of effect would be likely to ensue from the employment of the ether in a condensed, instead of in a more rarefied, form.