One morning as he leaned against the door-post, smoking his pipe and dreaming of that fine shop on the Boulevard de la Madeleine where Mme. Cibot, gorgeously arrayed, should some day sit enthroned, his eyes fell upon a copper disc, about the size of a five-franc piece, covered thickly with verdigris. The economical idea of using Cibot’s medicine to clean the disc immediately occurred to him. He fastened the thing in a bit of twine, and came over every morning to inquire for tidings of his friend the tailor, timing his visit during La Cibot’s visit to her gentlemen upstairs. He dropped the disc into the tumbler, allowed it to steep there while he talked, and drew it out again by the string when he went away. The trace of tarnished copper, commonly called verdigris, poisoned the wholesome draught; a minute dose administered by stealth did incalculable mischief. Behold the results of this criminal homoeopathy! On the third day poor Cibot’s hair came out, his teeth were loosened in their sockets, his whole system was deranged by a scarcely perceptible trace of poison. Dr. Poulain racked his brains. He was enough of a man of science to see that some destructive agent was at work. He privately carried off the decoction, analyzed it himself, but found nothing. It so chanced that Remonencq had taken fright and omitted to dip the disc in the tumbler that day. Then Dr. Poulain fell back on himself and science and got out of the difficulty with a theory. A sedentary life in a damp room; a cramped position before the barred window--these conditions had vitiated the blood in the absence of proper exercise, especially as the patient continually breathed an atmosphere saturated with the fetid exhalations of the gutter. The Rue de Normandie is one of the old-fashioned streets that slope towards the middle; the municipal authorities of Paris as yet have laid on no water supply to flush the central kennel which drains the houses on either side, and as a result a stream of filthy ooze meanders among the cobblestones, filters into the soil, and produces the mud peculiar to the city. La Cibot came and went; but her husband, a hard-working man, sat day in day out like a fakir on the table in the window, till his knee-joints were stiffened, the blood stagnated in his body, and his legs grew so thin and crooked that he almost lost the use of them. The deep copper tint of the man’s complexion naturally suggested that he had been out of health for a very long time. The wife’s good health and the husband’s illness seemed to the doctor to be satisfactorily accounted for by this theory. “Then what is the matter with my poor Cibot?” asked the portress. “My dear Mme. Cibot, he is dying of the porter’s disease,” said the doctor. “Incurable vitiation of the blood is evident from the general anaemic condition.”