Completing the puzzle of blood circulation: the discovery of capillaries.

Marcello Malpighi is considered to be the founder of microscopic anatomy. For almost 40 years he used the newly invented microscope to study and discover many structures of human body, animals and plants. One of his greatest contributions to science was the establishment by direct observation of an anatomical linkage between arteries and veins, the capillary network, a monumental work that completed Harvey's theory of blood circulation.