Who discovered the capillaries and how?

The Italian scientist by the name of Marcello Malpighi is accredited with discovering capillaries in 1661. Marcello Malpighi was "using a microscope" to examine "the brain and major organs" (Pearce JM, "Malpighi and the discovery of capillaries"). He first noted capillaries in the brain and spinal cord during his examinations. Many of Marcello Malpighi’s dissections were completed on frogs.  Malpighi reasoned that the capillaries connected veins and arteries. He hypothesized that this connection was needed to allow the blood that circulated throughout the body to "flow back to the heart" (Pearce). Hair-like capillaries are the body's smallest blood vessels and allow for exchange of wastes and nutrients, oxygen and carbon dioxide between tissues and blood (American Heritage Dictionary).