Marcello Malpighi

Founder of Microscopic Anatomy · Anatomist & Microscopist · 1628–1694

The anatomist who first saw capillaries through a microscope, supplying the one vessel William Harvey's proof of the circulation had been missing.

Who was Malpighi?

Marcello Malpighi was born near Bologna in 1628, the year Harvey published his demonstration that blood circulates. Harvey's argument had a hole in it: something had to join the arteries to the veins, and no instrument then available could show it, so he was reduced to insisting that connections must exist too small to see. In 1661, examining a frog's lung under a microscope, Malpighi saw them — a fine network of vessels carrying blood from artery to vein. He named them capillaries, and the circulation was complete four years after Harvey's death. He went on to apply the lens everywhere: the layers of the skin, the taste buds, the filtering bodies of the kidney, the air sacs of the lung, the anatomy of insects and plants, and the day-by-day development of the chick embryo. His colleagues at Bologna resented his methods and his students' hostility went as far as ransacking his house; he continued regardless and ended his career as physician to Pope Innocent XII.

Major achievements

• First observed capillaries, completing Harvey's account of the circulation
• Founded microscopic anatomy as a discipline
• Described the structure of the lung, skin, kidney, spleen and tongue
• Traced the development of the chick embryo day by day
• Pioneered the microscopic study of plants and insects

Life in brief

• 1628 — Born near Bologna: The same year Harvey published De Motu Cordis.
• 1656 — Professor at Pisa: Meets Borelli, who turns him towards the microscope.
• 1661 — Sees the capillaries: In a frog's lung — completing Harvey's circulation.
• 1666 — Describes the spleen and kidney: Finding filtering bodies nobody had suspected.
• 1669 — Elected to the Royal Society: Which publishes his work thereafter.
• 1673 — The chick embryo: Traces development day by day under the lens.
• 1684 — House ransacked: By hostile colleagues and students at Bologna.
• 1691 — Physician to the Pope: Moves to Rome in the service of Innocent XII.

Explore the life of Malpighi — five chapters

1. Bologna, and the Friend Who Turned Him Toward the Lens — An orphaned student and a new instrument
2. The Frog's Lung — Closing the circulation, 1661
3. Skin, Kidney, Spleen, Silkworm — Founding microscopic anatomy
4. The House Ransacked — What his colleagues thought of the microscope
5. The Names That Stayed — What survives of a life spent looking

Read the five-chapter life of Marcello Malpighi →

Where Malpighi appears in your course

Marcello Malpighi has a genuine claim on 8 lessons of the Pearson Edexcel International GCSE science course built into Incandio. Six of them:

• Blood Vessels and the Circulation — Biology: Harvey died in 1657 insisting that vessels too small to see must join the arteries to the veins. Four years later Malpighi put a frog's lung under a lens and watched blood pass through exactly such a network. He named them capillaries. It is the rarest thing in science — a prediction made without any means of testing it, confirmed almost exactly, by someone who never met the man who made it.
• Excretion: Getting Rid of What You Made — Biology: Turning his microscope on the kidney, Malpighi found it was not the solid mass it appeared to be but was packed with tiny knots of blood vessels and tubules — structures nobody had suspected, and which are still called Malpighian corpuscles. He could not say what they did, but he showed that excretion happens in machinery far below the scale anyone had been looking at.
• The Kidney and the Nephron — Biology: To the naked eye a kidney is a dense red mass with no visible structure at all. Malpighi put one under a lens and found it densely packed with tiny knots of blood vessels and fine tubules — a machine rather than a sponge. The knots are still called Malpighian corpuscles, and this lesson's nephron is what he was looking at without being able to say what it did.
• Ultrafiltration and Selective Reabsorption — Biology: Malpighi traced the fine tubules running from each of the knots of vessels he had found, and could describe their course precisely without any way of discovering what passed along them. This lesson is the answer to a question he could pose but not settle — and it is worth knowing that the structure was mapped almost two centuries before the mechanism was understood.
• The Human Reproductive Systems — Biology: Everything on this page exists to produce a fertilised egg cell, and Malpighi is the first person who set out to watch what one becomes. He opened chick eggs at intervals over successive days and drew what he found under the lens, tracing the development of the heart, the blood vessels and the nervous system from a structureless start. It was the first systematic account of an embryo developing rather than being assumed to exist fully formed and merely growing — which was the prevailing view he was arguing against.
• The Placenta and the Amniotic Fluid — Biology: Everything on this page happens across the wall of a capillary, and Malpighi is the person who found capillaries. In 1661 he examined a frog's lung under a microscope and saw the fine network joining artery to vein that Harvey had been forced to argue for without ever seeing. He then turned the same lens on the placenta and the developing chick embryo. Exchange between two circulations is only possible because the vessels involved are fine enough and thin-walled enough for substances to cross them, which is precisely what he was the first to observe.

Begin

• Start a conversation with Malpighi — a dramatised, historically grounded AI portrayal
• Read the Historical Brief
• Explore the life of Malpighi — five chapters
• Find your exam topics · Meet all 208 figures