- De humani corporis fabrica (on the fabric of human body),
By Andreas Vesalius

It was one of the earliest anatomy textbooks, written in 1543, that used real human cadavers to make observations and illustrations. It was a major milestone in the history of medicine

The circulatory system, as William Harvey imagined it

In ancient (Galenic) medicine, it was the liver that creates blood from the lacteals that deliver nutrients from the intestines. Then the inferior vena cava arises from the liver and delivers blood to the right side of the heart. It then goes to the lungs through the pulmonary arteries to "feed" them.

At the same time, the ancients believed, there were invisible pores in the septum of the heart which allow blood to seep through to the left side of heart. There, the pulmonary veins deliver "spirit" or vital air from the lungs to the heart where it gets mixed with blood in the left ventricle (and this explains the bright red color of arterial blood). Afterwards, the blood travels to the rest of the body through the aorta. Once it reaches its destination, it gets "consumed" by the organs of the body, so the liver has to make more blood, and so on ad infinitum.

Shit was weird

.

Baghdad,
As seen from the ISS on July 18th

Leviathan,
A book by Thomas Hobbes

The Destruction of Leviathan,
By Gustave Doré