That the confinement of human effluvia, along with heat and want of water, will produce a malignant fever, is certain from the example of the unfortunate people confined in the Black Hole at Calcutta. In this case the distemper seems to justify the opinion that plague may be artificially produced, perhaps more than any other upon record; for Dr. Ferriar informs us that it was attended with eruptions resembling those of the true plague. In this case, however, the confinement was beyond example in any situation which can be supposed incident to a city or camp. There is no country in the world where the inhabitants are equally numerous with those of the empire of China, its population at present being estimated by Sir George Staunton at _three hundred and thirty-three millions_, a number equal to _one third_ of the supposed inhabitants of the whole globe; of consequence the cities must be immensely crowded with inhabitants; yet it remains free from plagues. Human effluvia therefore, in the most populous state in which mankind can exist in society, _are not_ able to taint the atmosphere of a country or city. The following is Dr. Clark’s account of that celebrated empire: “The whole empire of China is represented to be extremely delightful; the soil rich, the air pure, and the industry of the inhabitants astonishing. As it produces every luxury and necessary of life, it is justly esteemed one of the most fertile countries in the world. As the Chinese prohibit emigration, and seldom or never engage in war, their country is extremely populous. Every river maintains a proportion of inhabitants adequate to the land, whose families live continually in boats, without having any other place of residence. Their number of people lays them under the necessity of carrying industry to the greatest height; for otherwise their country, fertile as it naturally is, would be insufficient to maintain the inhabitants. Every inch of land is cultivated; no forests nor woods, nor even a single tree, is suffered to obstruct the labours of the husbandman. Canals are cut every where to water the fields, and marshes are manured for the cultivation of rice. By these means health and plenty are, in a great measure, the portion of its inhabitants through all the seasons of the year. The only terrible and fatal diseases to which they seem to be subject are the small-pox and leprosy.”