All this while his health was steadily improving. The menace of consumption was removed; and though he suffered from severe attacks of pain in the side, the cause of this persistent malady does not seem to have been ascertained. At Naples he was under treatment for disease of the liver. Afterwards, his symptoms were ascribed to nephritis, and it is certain that his greater or less freedom from uneasiness varied with the quality of the water he drank. He was, for instance, forced to eschew the drinking water of Ravenna, because it aggravated his symptoms; while Florence, for a similar reason, proved an unsuitable residence. The final settlement of the Shelleys at Pisa seems to have been determined by the fact that the water of that place agreed with him. That the spasms which from time to time attacked him were extremely serious, is abundantly proved by the testimony of those who lived with him at this period, and by his own letters. Some relief was obtained by mesmerism, a remedy suggested by Medwin; but the obstinacy of the torment preyed upon his spirits to such an extent, that even during the last months of his life we find him begging Trelawny to procure him prussic acid as a final and effectual remedy for all the ills that flesh is heir to. It may be added that mental application increased the mischief, for he told Leigh Hunt that the composition of "The Cenci" had cost him a fresh seizure. Yet though his sufferings were indubitably real, the eminent physician, Vacca, could discover no organic disease; and possibly Trelawny came near the truth when he attributed Shelley's spasms to insufficient and irregular diet, and to a continual over-taxing of his nervous system.