Dr. Fritz Kahn was a Berlin based gynecologist who wrote and illustrated a number of popular science books that showed the processes of the human body as though they were machines.
While the metaphors may be limited in terms of actually understanding biological functions, they make for great imagery.
Kahn was active in the 1920’s. In the 1930’s his books were banned by the Nazis and copies were burned along with other works by Jewish intellectuals. He was expelled from Germany, and just before the onset of WW II, escaped from Europe to the U.S. with personal help from Albert Einstein.
There is a website devoted to Kahn and his work, that includes a gallery.
A large reproduction of the image above (shown with details) can be found at the National Library of Medicine as part of their Dream Anatomy feature (see my post on Dream Anatomy).
His book, Fritz Kahn: Man Machine Maschine Mensch is still available in an edition that includes both the original German text and an English translation.
Henning M. Lederer has created an animated and interactive interpretation of the work above, for which there is a preview video on YouTube.
[Via Cyriaque Lamar on io9]