"Of the various evils recounted in connection with the subject of houses, there are two which deserve special attention. Many facts, besides those associated with the holds of vessels, justify the belief that the growth of the poison of yellow fever is specially favoured in warm, moist, ill-ventilated places, where air is closely confined. The low-lying floors touching the earth, the small, densely packed houses, the unusually contracted ventilating space in their rear, the large unventilated excavation for privies and sinks, all furnish, as is firmly believed, the most favourable breeding-places for the poison of yellow fever. In addition, statistics prove that in great cities subjected to their ordinary unfavourable conditions, the denser their population the sicklier and shorter-lived their inhabitants. Common-sense and experience unite to teach that the denser a population the more widespread and frightful the havoc of diseases, especially of communicable diseases. Elsewhere will be found a special report on the density of the population of Havana compared with numerous other cities, and it therein appears that more than three-fourths of the people of Havana live in the most densely populated localities in the world. A tropical climate renders this enormous evil still greater. Not only in Havana but throughout Cuba the average number of inhabitants to each house is unusually great, and this fact enables us better to understand the great prevalence in Cuba of those communicable diseases which its climate and other local conditions favour. "The Registry Office in Havana reports that there are upwards of eighteen thousand fincas in this registry district, which comprises the village of Marianao in addition to the city of Havana. "A finca is a piece of land, with definite boundaries or limits whether large or small, and whether it has buildings on it or not. "Of the eighteen thousand fincas in the district about fourteen thousand have houses upon them, and the other four thousand being vacant lots in the city, or fincas rusticas, in the rural districts. "At least twelve in every thirteen inhabitants live in one-story houses; and as the total civil, military, and transient population exceeds two hundred thousand, there are more than twelve inhabitants to every house. Tenement houses may have many small rooms, but each room is occupied by a family. Generally, the one-story houses have four or five rooms; but house-rent (as also food and clothing) is rendered so expensive by taxation, by export as well as import duties, that it is rare for a workman, even when paid fifty to one hundred dollars a month, to enjoy the exclusive use of one of these mean little houses. Reserving one or two rooms for his family, he rents the balance. This condition of affairs is readily understood when it is known that so great a necessity as flour costs in Havana $15.50, when its price in the United States was $6.50 per barrel.