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Peter's Research and Studies
Each student at Oxford negotiated with his tutor a program of study, which included the level of standard to which the student would be held. Standards could be set low enough to allow students to focus on partying and social life (a "pass" degree) or set as high as to require high scores on rigorous examinations (leading to a degree labeled First, Second, or Third).

Peter Medawar graduated with a First. Because his interest was well kindled in zoology, he stayed on as a graduate student at Oxford. He plunged into research on embryos, using the then revolutionary technique of culturing cells. His first studies identified a compound in malt extract that inhibited connective tissue cells in culture. He showed the first draft of his manuscript describing the research to Howard Florey, the discoverer of penicillin. Florey pulled no punches in denouncing the paper, saying that "it sounds more like philosophy than science." Despite the criticism, Florey encouraged him to fix the paper and to pursue his line of research, putting him in touch with chemists with whom he could consult to learn more about the mysterious inhibitory compound. Peter never identified the chemical nature of this compound. In the meantime, he did use the malt extract to study the mathematics that describe growth of cell in culture.

While conducting his research, Peter also worked in Florey's laboratory, where everyone studied wound and burn healing to aid in the World War II effort in Britain. At that time, people with severe burns were kept alive with blood transfusions and sulfa drugs to combat infections. This created a problem as the burned tissue would fall away and leave in its place raw areas that were very vulnerable to infection. Peter tested a variety of antibacterial substances, finding that some of the sulfa drugs were effective when applied as a powder to the raw areas. In a tissue culture, one sulfa drug's crystals actually enhanced the ability of epithelial cells to spread, using the crystals as a support "pole" for tent-like coverings. Thus, this drug not only reduced infections but also accelerated the covering of raw burn areas by new skin growth.

These war wound experiences also shaped Peter's future research. He became intrigued with the fact that skin grafts only worked if the grafted skin came from the same person receiving the graft. Somehow, the body could recognize alien tissue and would not accept it. How? He took on this problem as his "duty and pleasure" to investigate. As World War II continued in Europe, he applied for and received a grant to study the issue in a surgical unit where there were plenty of patients with skin wounds needing grafts.

One of his first clues was the observation that a second graft of "foreign" skin did not last as long as the first one. This suggested that the body had some kind of memory of the first graft experience. He and his colleague, Tom Gibson, published a paper on the data and concluded that the body has a mechanism that resists alien tissue, much like the mechanism by which the body resists other foreign invaders, such as bacteria, viruses, and parasites. The mechanism allows the body to adapt to or reject foreign intrusion. Moreover, the resistance system can retain a residual memory and respond even more vigorously at the second time of exposure.

Peter then embarked on a large program involving animal testing of skin-graft rejection. He cut and stained tissue samples taken from the grafts and observed cellular changes occurring at various stages of graft rejection. Because the war was in full sway, Peter had little help. He was responsible for all of the animal feeding, surgeries, nursing care, and laboratory work. He felt guilty if he did less, though he took some comfort from the fact that he was helping to develop treatments for war injuries. He was also proud to be teaching medical students who would become the doctors saving lives during the war. He acquired the habit of working long days and bringing home a briefcase of documents to read before the next morning.

Peter's most important work was to demonstrate that the rejection of donor grafts was due to an immunological reaction and that tolerance could be built up by injections into embryos. Thus was born the idea of acquired immunological tolerance, an idea that is still spawning new research to this day, because how this tolerance develops is still not fully understood. The body's capacity for reacting to foreign proteins can be reduced by repeated exposure to the protein, preferably in small, graded amounts.  Applications of Peter Medawar's research include the common practice of treating allergies with allergy shots and of reducing rejection of tissue transplants. Although most of his work was immediately accepted and appreciated by his peers, Peter is often quoted for the famous quip:

The human mind treats a new idea the way the body treats a strange protein -- it rejects it.

For his important discoveries, Peter was awarded the Nobel Prize in 1960. It was his research on tissue transplantation which eventually helped make organ transplants possible.

His book, "Advice to a Young Scientist," has been widely read and is still available at

Medawar, Peter. 1990. The Threat and the Glory.  Reflections on Science and Scientists. Harper Collins. New York, N.Y.
Medawar, Peter. 1986. Memoir of a Thinking Radish. Oxford University Press, Oxford, England.
Medawar, Peter. 1973. Advice To A Young Scientist. Harper and Row, New York. Biographical sketch Biographical sketch - In Memoriam Testimonial

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