Wollaston's attempt to demonstrate the presence of glucose in the blood serum of diabetics was unsuccessful due to the limited means of detection available to him. His 1811 paper "On the non-existence of sugar in the blood of persons labouring under diabetes mellitus" concluded that sugar must travel via lymphatic channels from the stomach directly to the kidneys, without entering the bloodstream. Wollaston supported this theory by referring to the thesis of a young medical student at Edinburgh, named Charles Darwin, titled, "Experiments establishing a criterion between mucaginous and purulent matter. And an account of the retrograde motions of the absorbent vessels of animal bodies in some diseases." The medical student was the uncle of the more famous Charles Robert Darwin.