Montaigne, the great philosopher of the sixteenth century, has given a most graphic description of the symptoms of "stone," tinged by the unmitigated reality of personal experience, since he himself was a sufferer for many years: Thou art seen to sweat with pain, to look pale and red, to tremble, to vomit well nigh to blood, to suffer strange contortions and convulsions, by starts to let tears drop from thine eyes, to urine thick, black, and frightful water, or to have it suppressed by some sharp and craggy stone that cruelly pricks and tears thee. However, he never reached "such a degree of despair as to bellow and make uproar." He traveled much, seeking a cure at the various watering places of Europe, but without success. Through the centuries the cause of the formation of stone remained obscure. However, during the last few years knowledge of the causes and prevention