The Statistical Society of London some time ago appointed a Committee of its Council to make a house-to-house examination of the parish of Marylebone, with a view to ascertain how many families in the parish occupied a single room as a living and sleeping room. In the course of this inquiry, one of the examiners came to a house in which there was one remarkable room. It was occupied not by one family only, but by five. A separate family ate, drank, and slept in each of the four corners of this room; a fifth occupied the centre. “But how can you exist,” said the visitor to a poor woman whom he found in the room (the other inmates being absent on their several avocations), “how can you possibly exist?” “Oh, indeed, your honour,” she replied, “we did very well until the gentleman in the middle took in a lodger.” I see every day in the wards of the Fever Hospital the consequence of taking in such lodgers. An epidemic shows it not more truly, but more strikingly. Within the walls of an establishment for pauper children at Tooting, in 1849, there were crowded 1395 children. Little more than one hundred cubic feet of breathing space was allowed for each child, 500 being the smallest compatible with safety. One night Cholera attacked sixty-four of these children; 300 were attacked in all. Within a week 180 perished. In the Workhouse of Taunton there were 276 inmates. In some of the rooms the breathing space was not more than sixty-eight cubic feet. Cholera swept away 60 of these inhabitants in less than a week. In the County Jail of this same town, the breathing space allowed to each prisoner ranges from 819 to 935 cubic feet. Not a single case of cholera, nor even of diarrhœa, occurred among the prisoners in this jail. The town’s people also escaped, while in the overcrowded workhouses, 22 per cent. of the total number of the inhabitants were swept away. In the village of East Farleigh, near Maidstone, 1000 persons were assembled for hop-picking. They were lodged in sheds, and had about eighty cubic feet for breathing space: in a few days diarrhœa became universal among them: ninety-seven were attacked with cholera, and forty-six died. In the same village, at the same time, under another employer who had provided proper accommodation for his labourers, there was a complete immunity from the epidemic. I could add cases of the like kind without number. I could show that animals are affected by this cause of disease no less than men; that horses overcrowded in stables die of glanders; dogs in overcrowded kennels die of distemper; sheep overcrowded in ships, even during a short passage from one country to another, die in great numbers of febrile diseases:[5] results which prove the operation of a general law of nature. I could adduce equally decisive examples of the action of each of the principal external predisposing causes just enumerated.