The overall structural organization of the kidney, its vasculature and its excretory units, the nephrons, was the subject of intense study and disagreement for hundreds of years. In 1783, Schumlansky received a doctoral degree with the dissertation De structura renum, in which he presented a detailed and comprehensive description of the major blood vessels of the kidney, the blood vessels of the medulla and pyramids of Ferrein and the malpighian glandula. He concluded the dissertation with a description of 3 experiments on a pig kidney, deducing a connection between the glomerulus and the uriniferous tubule, though his illustration of it was far from convincing. It was only 59 years later that Bowman proved Schumlansky to be correct.