William Harvey and the Discovery of the Circulation of the Blood
by Thomas H. Huxley
There is no easily accessible online text with images for this book, but you can refer to these as you read the text. Baylor University has a summary of Harvey's discovery with modern illustrations.
A summary of persectives on the vascular system by Erasistratus, Galen, Colombo (Realdus Columbus), and Harvey with schematics here
4-minute basic illustration of the circulatory system on YouTube. The text is read by a robot, but the graphics are pretty good.