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Animals and Medicine

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Jack Howard Botting

III. Drugs for Organic Diseases

15. Early Animal Experiments in Anaesthesia

Note de l’auteur

An earlier version of this chapter was published as: Early animal experiments in anaesthesia. RDS News July 1992 4-5.

Texte intégral

1In an attempt to make the history of scientific developments readable authors tend to highlight bizarre and amusing incidents, sometimes to the extent of inadvertently misleading the reader.

2Thus most essays that purport to describe the background to the introduction of general anaesthesia to surgery inevitably refer to the laughing gas parties or ether frolics that were apparently commonplace in the 1840s (see (1) for example). The inhalation of nitrous oxide or ether produced instantaneous elation or inebriation. Social occasions where this activity was indulged were presumably more benign equivalents of today’s glue sniffing sessions or Ecstasy parties. The conventional story is that accidental injury sustained during such a party was not noticed until well after the effects of the inhaled substance had worn off, suggesting to the astute observer that the apparent analgesic action of the inhalants might be of use in surgery. A good story, but is it true? The answer is only partially.

3Fifty years before an anaesthetic was used in patients Humphrey Davy had demonstrated that nitrous oxide produced a state of unconsciousness in animals that was reversible if the animal was returned to air. He described the administration of nitrous oxide to a “stout and healthy cat” (2):

after 5 minutes the pulse was hardly perceptible; he made no motions and appeared wholly senseless. After 5 minutes and a quarter he was taken out… in 8 or 9 minutes he was able to walk… in half an hour he was completely recovered.

4Davy similarly described the effect of breathing a mixture of 1 part oxygen and 3 parts nitrous oxide on a guinea pig:

... in 2 minutes reposed on his side, breathing very deeply... he lived quietly for near 14 minutes. He was taken out and recovered.

5These experiments led Davy to conclude that animals could survive for long periods in an atmosphere of nitrous oxide mingled with air, and he subsequently inhaled the gas himself noting on one occasion that the gas relieved the pain caused by a wisdom tooth.

6In his book Researches published in 1800 Davy concludes:

As nitrous oxide in its extensive operation appears capable of destroying physical pain, it may probably be used with advantage during surgical operations in which no great effusion of blood takes place.

7Henry Hickman, a practitioner at Ludlow in Shropshire, took the experiments a stage further by actually performing surgery on animals during a state of “suspended animation” induced by inhalation of carbon dioxide or nitrous oxide (3). As a result of his experiments Hickman tried to direct the attention of the medical profession in Britain (and later in France) towards the possibility of preventing pain during surgical operations by the inhalation of these gases (Fig. 15.1). However, his pamphlet: “A letter on Suspended Animation containing experiments showing that it may safely be employed during operations on animals with the view of ascertaining its probable utility in surgical operations on the Human Subject,” appears to have been totally ignored by the Royal Society, before whom it was laid in 1823.

Fig. 15.1 Watercolour of Henry Hickman by Richard Cooper, painted in 1912. Hickman was a pioneer of anaesthesia, successfully performing surgery on animals anaesthetised with carbon dioxide as early as the 1820s. Wellcome Library, London, CC BY.

8It was not until over 20 years later that the dentist Horace Wells, under nitrous oxide anaesthesia, had a wisdom tooth removed by his partner Riggs. The nitrous oxide was administered (at the behest of Wells) by Quincy Colton, a onetime medical student who made his living by demonstrating the effects of laughing gas on members of the audience at his stage shows. By 1846 major operations in both America and Britain were being performed under anaesthesia with ether, which Charles Jackson and Morton (an ex-partner of Wells) had found to produce a less erratic induction than the gas nitrous oxide, which only came into its own in 1868 when it was available compressed into cylinders. During the acrimonious dispute amongst the claimants that followed the announcement by the United States of a substantial prize for the inventor of anaesthetics, Jackson gave credit to Humphrey Davy when he wrote: “I have in former publications stated, as I do now, that my attention was first awakened to this subject while a student of medicine, by reading Davy’s researches.” (4)

9It is clear that animal experiments paved the way towards the development of general anaesthetics and should have ensured their acceptance 50 years earlier but for societal reasons. The blossoming of humanitarianism and philanthropy that characterised the Victorian era fostered the desire to alleviate all suffering, even that of childbirth which was held to have authoritative support in the Book of Genesis.

10It was the desire to find the perfect anaesthetic for the pain of childbirth that lead Simpson, the Professor of Midwifery at Edinburgh University, to search for an alternative to ether. Ether was not only an irritant but also inflammable, a risk when it was used in candlelight. Amongst other investigations he attempted to persuade Wemyss Reid to allow him to inhale ethylene dibromide, which had recently been prepared in the latter’s laboratory. Wemyss Reid quite rightly insisted that the liquid should first be tested on rabbits. Two were subjected to the vapour, quickly passed into anaesthesia and in due course recovered. The following day Simpson intended to test ethylene dibromide on himself and his assistant but sensibly did not proceed with the experiment upon discovering that the two rabbits had died overnight (5) (ethylene dibromide is used today as a soil fumigant to destroy nematodes; it causes pulmonary congestion and depression of the central nervous system if inhaled). This was probably one of the earliest examples of the necessity of preliminary animal testing before phase one clinical studies.

11Simpson eventually obtained a sample of chloroform (Fig. 15.2), a substance which had been tested on animals by Flourens and shown to produce unconsciousness (6).

Fig. 15.2 Drawing of Sir James Young Simpson and friends by unknown artist, representing Simpson’s discovery of the anaesthetic properties of chloroform in humans. Previously tested by Flourens on animals in the 1840s, chloroform was used almost immediately by Simpson to ease the pain of childbirth. Wellcome Library, London, CC BY.

12Simpson used chloroform in midwifery and produced a paper describing its effects in November, 1847. As a result, chloroform rapidly came into use in general surgery and for a while was believed to be absolutely safe. However the first death under chloroform anaesthesia occurred two months later in January, 1848 (3) and there followed a high incidence of intraoperative and postoperative deaths due to the hepatotoxic and cardiotoxic actions of this anaesthetic. Animal rights propaganda, however, frequently avers that “chloroform is a useful anaesthetic for people, but poisonous to dogs.” (7) Its dangers to patients are obvious but where is the evidence that it is inordinately toxic to dogs? Wakely in 1848 (8) compared the effects of ether and chloroform on 100 animals of various species. Out of 32 animals anaesthetised with ether, 11 died (34%). A total of 67 animals were given chloroform and 30 died (44%). Of the 17 dogs given chloroform only 4 died (24%). Hardly evidence for a selective toxic action.

13It is clear that those who wish to promote the animal rights case on what are claimed as “scientific grounds,” can carefully select the evidence they choose to transmit and so put forward an apparently plausible argument. However, omission of evidence can result in a misinterpretation of history. Whatever one considers the morality of a particular crusade, facts should be sacrosanct.

Bibliographie

References

1) Sharpe R (1988) The Cruel Deception: The Use of Animals in Medical Research. London: Thorsons.

2) Livingston A (1983) in Discoveries in Pharmacology vol. 1 ed Parnham M J & Bruinvels J, Amsterdam: Elsevier.

3) Hewitt F (1912) Anaesthetics and their Administration, London: Macmillan & co.

4) Jackson C T (1861) A Manual of Etherisation, Boston: Mansfield.

5) Youngson A J (1979) The Scientific Revolution in Victorian Medicine, London: Croom Helm.

6) Flourens (1847). Note touchant l’action de l’ether sur les centres nerveux. Comptes rendus 24 340-44.

7) NAVS Leaflet, Bitter Pills, The human consequences of testing drugs on animals.

8) Wakely T H (1848) One hundred experiments on animals, with ether and chloroform. The Lancet i 19.

Table des illustrations

Légende Fig. 15.1 Watercolour of Henry Hickman by Richard Cooper, painted in 1912. Hickman was a pioneer of anaesthesia, successfully performing surgery on animals anaesthetised with carbon dioxide as early as the 1820s. Wellcome Library, London, CC BY.
URL http://books.openedition.org/obp/docannexe/image/1988/img-1.jpg
Fichier image/jpeg, 28k
Légende Fig. 15.2 Drawing of Sir James Young Simpson and friends by unknown artist, representing Simpson’s discovery of the anaesthetic properties of chloroform in humans. Previously tested by Flourens on animals in the 1840s, chloroform was used almost immediately by Simpson to ease the pain of childbirth. Wellcome Library, London, CC BY.
URL http://books.openedition.org/obp/docannexe/image/1988/img-2.jpg
Fichier image/jpeg, 45k

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