An Introduction to the Study of Experimental Medicine

Summary

Claude Bernard published this book in Paris in 1865 as the opening of a larger treatise on experimental medicine that he never completed. It sets out, for physicians, the method by which he had made his own discoveries, and argues that medicine must become a science grounded in physiology and the laboratory. The library text is Henry Copley Greene's 1927 English translation, complete, with an introduction by the Harvard biochemist L. J. Henderson, from an OCR scan with the index omitted. Part One, on experimental reasoning, distinguishes observation, in which the investigator notes phenomena as nature presents them, from experiment, in which he varies conditions on purpose; both end in an observed fact. Reasoning runs from an observed fact to an idea, from the idea to an experiment designed to test it, and from the experiment to a new observation. Bernard insists that the idea, or hypothesis, is the driving force of discovery, yet the experimenter must doubt it and submit it to counterproof, removing the supposed cause to see whether the effect also disappears. He calls theories partial and provisional truths, steps for further work, and warns against systems, against authority, and against the pride that turns scientific disputes into personal ones. Part Two, on experimentation with living beings, defends the claim that the same absolute determinism governs living and inorganic bodies; vital phenomena have physico-chemical conditions that can be known and controlled. The higher animals are partly freed from outer conditions because their cells live in an internal environment of blood and fluids kept relatively constant. Bernard discusses the choice of animals, the use of comparative experiments, the dangers of averages and statistics that blur real physiological states, and the moral question of experiment. He holds that no experiment injurious to a patient may be done on a human being, even for the good of others, and that vivisection of animals is justified by its usefulness to human life, though he recognizes and answers the feelings of its opponents. Part Three applies the method to cases from his own research: the discovery of sugar formation in the liver, which began from an unexpected result; experiments on the cause of death by carbon monoxide; the action of curare on the motor nerves; and examples of faulty reasoning by others. He concludes by describing the obstacles to experimental medicine, including empiricism without understanding, rigid doctrines and the reliance on the hospital alone, and calls the laboratory the true sanctuary of medical science.

Top Lessons

• An idea must be tested, not loved

  Bernard makes the hypothesis the starting point of discovery, but he asks the investigator to doubt his own idea and to seek the counterproof that could overturn it. The great principle of the method is doubt, not scepticism: belief that nature is lawful, joined with distrust of any present theory.

• Chance favours the prepared observer

  Bernard's discovery of sugar formation in the liver began when an experiment gave a result he did not expect. Instead of discarding it, he formed a new hypothesis and tested it. He presents the unforeseen fact as a gift that only an attentive and well-trained mind can use.

• Limits on what may be done to a patient

  Bernard holds that it is the physician's duty to experiment on a patient only for that patient's own benefit and never to do harm for the sake of science. He distinguishes injurious, innocent and beneficial experiments and draws a firm line around the first.

• The body keeps its own inner world

  Bernard's account of the internal environment explains how warm-blooded animals stay active through heat and cold: their cells live in fluids regulated to remain fairly constant. The idea joins physiology to medicine, since disease can be read as a disturbance of that inner balance.

Verified Quotes

Medical Lens

This is a founding text of laboratory medicine and of physiology as the basic science of medicine. Its concept of the internal environment, the regulated fluid world of the body's cells, was later developed by Walter Cannon as homeostasis and underlies modern thinking about physiological regulation and its disturbance in disease. Bernard's use of poisons (curare at the junction of nerve and muscle, carbon monoxide binding haemoglobin) as tools to dissect function is the template of experimental pharmacology, and his insistence that a drug's action be understood mechanistically rather than empirically anticipates the aims of psychopharmacology. His critique of averages and statistics, which he thought blurred real physiological states, is a period position that later clinical trial methodology answered; readers can treat it as part of a debate rather than a settled verdict. His rule that no experiment injurious to the patient may be done on a human being is an early formal statement of a principle later written into research ethics codes, and his defence of vivisection, with its acknowledgement of opponents' feelings, records one side of a debate that divided his own household. His claim that the insane no longer learn from experience is a passing remark, not a psychiatric theory.

• Part One, Chapter I

  Bernard notes that the insane, having lost reason, no longer learn from experience, which he calls the prerogative of reason.

• Part Two, Chapter I

  The internal environment of warm-blooded animals and its protective mechanisms are described as the condition of their apparent independence from the outer world.

• Part Two, Chapter I

  Death by carbon monoxide is explained by its firmer union with haemoglobin than oxygen, as an example of how far physiology can answer the question how.

• Part Two, Chapter II

  Bernard sets out which experiments on human beings are forbidden, permitted or obligatory, and defends vivisection while discussing the pain of animals and the objections of its critics.

• Part Two, Chapter II, section on averages and statistics

  Bernard argues that averaging urine or blood analyses, or pulse rates, produces a state that does not exist in any real animal.

• Part Three, Chapter I

  Bernard recounts poisoning frogs with curare and performing a physiological autopsy, which showed that the poison abolishes the action of motor nerves while muscles remain excitable; he follows it with his experiments on death by carbon monoxide.

• Part Three, Chapter I

  Bernard narrates how an unexpected finding of sugar in the blood led to his discovery of the glycogenic function of the liver.

• Part Three, Chapter IV

  Empirical physicians who know that a remedy works but not how are contrasted with experimenting physicians who seek the mechanism of drug action.