Bernard (1813–1878)

Claude Bernard, the "father of modern experimental medicine", died a revered scientist. His attitude to the use of animals and anaesthetics in physiological research was influenced by Magendie under whom he studied from 1834 to 1843. Unlike Magendie, Bernard could not claim ignorance to justify the exclusion of anaesthetics from most—but not all—of his animal studies [19]; nor could he claim adherence to the vitalist principle which he described as being, "entirely contrary to science itself". Bernard's considerable contributions to anaesthesia [32] were anthropocentric and achieved at cost to the animals involved. He studied vasomotion—the nervous control of blood vessel diameter—by cutting projections from the stellate ganglion in unanaesthetized rabbits (so discovering cervical sympathetic block and its e ffects on the eye). His most influential and controversial work—on curare—began in 1844. (Curare is a drug derived from tree bark and applied to blow-dart tips used by South American Indians to paralyse and capture animals. Curare prevents muscle contraction and stops all movement, including breathing. However, it does not a ffect the central nervous system and so darted animals su ffocate whilst being fully conscious. If breathing is artificially supported, a curarised animal can be subjected to surgery and, although fully aware of the process, is unable to move—or vocalize—in agonized protestation.) Having demonstrated its neuromuscular blocking e ffect in frogs, he used it in dogs to control strychnine-induced convulsions. After further ranine studies, Bernard suspected that death following curare was caused by asphyxia and not loss of consciousness [33]. The realisation that it did not render the animal insentient prompted him to reflect:

*"in the animals, one can judge sensitivity only by motor manifestations. Man alone, on recovering from poisoning by curare, would be able to say, supposing that he had retained the memory, whether or not he had su*ff*ered".*

He wrote eloquently, and more than once, on his impression of death following curare administration:

*"Within the motionless body, behind the staring eye, with all the appearance of death, feeling and intelligence persist in all their force. Can we conceive of a su*ff*ering more horrible than that of intelligence present, after succumbing, one by one, of all the organs which are destined to find themselves imprisoned alive within a cadaver?"*

This concern did not prevent Bernard from continuing to use curare rather than anaesthetics in his experiments. Furthermore, he promoted its use in experiments to other physiologists. An 1864 essay asserts that the 'poison becomes an instrument which dissociates and analyses the most delicate phenomena of the living machine' [34]. Consequently, vivisectors discovered that used in the right quantities, curare made invasive procedures much easier and the drug became a common experimental tool in physiological practice.
