The leprosy, the pork measles and the _mesellerie_ were then only clinical forms of a single affection of a contagious nature—a hereditary disease whose symptoms appeared successively on the skin, in the mucous membranes, the viscera and in the nervous system. It then required a diathesis, which resembled greatly in its evolution that of syphilis, with which it has often been confounded. The physicians of leper hospitals have left behind a great number of medical documents bearing on the characteristics of the disease, but their observations are so confused that we can only conclude that they considered all cutaneous maladies as belonging to the same constitutional vice. They recognized, however, the _ladrerrie_ (disease arising from measly pork), by the following symptoms, the same being laid down by Guy de Chauliac: “Eyelids and eyebrows swollen, falling of eye-lashes and eyebrows, which are replaced by a finer quality of hair; ulceration of septum of the nose, odor of ozoena, granulated tongue, fœtid breath, painful breathing, thickening and hardness of the lips, with fissures and lividity of same; gums tumefied and ulcerated; furfuraceous scales in the hair, purple face, fixed expression, hideous aspect; forehead smooth and shiny like a horn; pustules on face; veins on chest much developed; breasts hard.” “Thinness of muscles of the hand, especially thumb and index finger; lividity and cracking of the nails; coldness of the extremities; presence of a serpiginous eruption; insensibility of the legs, collections of nodosities around the joints; under the influence of cold elevations appeared on the cutis, making it appear like goose-skin.” “Sensation of pricking, ulcerations of skin; sleep uneasy, fetidity of sweat; feeble pulse, bad odor of blood, which is viscid and oily to the touch and gritty after incineration, likewise of a violet black color.” The contagious characteristic of leprosy through sexual relation was noticed by physicians attached to hospitals, and was the subject of police restriction by public sanitary officers. Thus in the thirteenth century the celebrated Roger Bacon, surnamed the admirable doctor, wrote that commerce with a leprous woman could be followed by very serious consequences. This opinion was corroborated by a physician of the University of Oxford, his contemporary John of Gaddsen, and by the observations of Bernard Gordon, a celebrated practitioner of Montpellier. We all know the history of a Countess who came to be treated for leprosy at Montpellier, when a Bachelor in Medicine charged with the task of dressing her sores, fell desperately in love with the leper lady, and from his _amours_ contracted most serious cutaneous disease.