The observations of Marcello Malpighi (1628–1694) were forever to change the science of embroyology, histology, and pathology. Many a fierce battle was fought between Malpighi and his opponents steeped in ancient views and Galenism, even to the point of actual assault by masked colleagues.

Born in the year when Harvey published his historic work, Malpighi was to make Harvey's theory a reality 33 years later. By the age of 28, Malpighi was a professor at The University of Pisa. A few years later, he returned to Bologna, Italy, and embarked on numerous publications, but encountered hostility and fierce opposition from obstinate champions of Galenism. When he left Bologna for Messina, similar opposition followed. He again returned to Bologna and was elected to the Royal Society of London in 1669. Eventually, Malpighi moved to Rome and became physician to Pope Innocent XII.

Malpighi was a pioneer with the microscope, opening up new frontiers in a new and hitherto unseen world. Some of his most notable works include a botanical treatise, Anatomia plantarum; his writings on the silkworm; and De pulmonibus, a meticulous study of lung histology. Malpighi discovered the missing link in Harvey's theory, the capillary, using an ideal preparation—the almost transparent frog lung. Harvey had not used a microscope and did not have definite proof of the existence of capillaries.

Malpighi described red blood corpuscles in 1665 and studied the histology of the liver, spleen, and renal glomeruli. Malpighian corpuscles of the spleen and the malpighian layer of skin still bear his name. Malpighi also gave an account of lymphadenomatous proliferations in the spleen, which were subsequently described in a series of cases by Hodgkin in 1832 and named Hodgkin's disease by Wilks in 1856. Malpighi also described aortic pathology and osteomyelitis, and wrote against the concept of “spontaneous generation.” Applying his microscope to the chick embryo, Malpighi recorded, in minute detail, the mysteries of the embryo. His Royal Society memoirs, De formatione pulli in ovo and De ovo incubato, surpassed all contemporary texts. The illustrations accompanying these timeless texts are astounding in their accuracy. Malpighi's depiction of the embryo from the very first hours of incubation and the developmental sequence of the rudimentary brain, the cerebral vesicles, optic vesicles, somites, heart, aorta, and other structures are accurate to this day.

Malpighi died of apoplexy on November 29, 1694. Not unlike the academic climate that prevails today, the life of this intellectual giant and scientific genius was embittered by persistent attacks from academic peers; but his creativity, genius and scientific honesty left a timeless legacy.