Gall was led to believe that the brain is not, as previously thought, a pulpy substance, but must be a membrane due to the integrity of mental faculties in cases of significant true internal hydrocephalus, meaning accumulations of water in the brain cavities, where the entire brain is often stretched into a membrane that is barely a line thick. At the same time, pathological phenomena, particularly the paralysis of the limbs following injuries to the hemispheres of the brain, drew his attention to the necessity of an uninterrupted connection between these and the spinal cord. Thus, Gall endeavored to anatomically demonstrate this connection as well as the membranous nature of the brain, and he was rewarded for the immense diligence and effort he devoted to this over several years by the confirmation of his hypotheses based on physiological grounds.