De humanis Corpore is an unpublished textbook Leonardo Da Vinci was working on for a large portion of his life. The textbook was planned to have been finished in 1516 CE but Leonardo Da Vinci never finished the book. It was planned to have 120 sections with extensive amounts of illustrations. The textbook was meant to explain each of the organs and apparatus’ of anatomy, physiology, and pathology in the human body. A section of the book was also going to be dedicated to a comparative discussion of human and animal anatomy. The textbook was largely finished and it is known that Leonardo employed two collaborators to organize the drawings (268 pages of anatomical drawings) and annotations he had wrote. It is theorized that Leonardo chose not to publish and finish his textbook due to being afraid of the textbook being too controversial for this time period. This theory was proposed because in his drawing of the heart and blood circulation Leonardo wrote “I could tell more, if I was allowed to do so.”

Source:

Sterpetti, Antonio V. The Revolutionary studies by Leonardo on blood circulation were too advanced for his time to be published. Journal of Vascular Surgery 2015, vol 62 (1): 259-263. DOI:https://doi.org/10.1016/j.surg.2015.10.001

Image Source:

Sterpetti, Antonio V. Anatomy and physiology by Leonardo: The hidden revolution?. Surgery 2016. Vol 159 (3): 675-687. DOI:https://doi.org/10.1016/j.surg.2015.10.001.