HONG KONG, 1912.
(6.)-PUBLIC HEALTH AND SANITATION.
251
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There has been great activity in regard to building operations during the past year, to meet the urgent demands for house-room created by the immigration of some forty to fifty thousand Chinese who poured into Hong Kong during 1911. These people were of all classes, and came principally from the neighbouring provinces of Kwangtung, Kwangsi and Fokien, seeking refuge from the political unrest which ultimately led to the overthrow of the dynasty and the establishment of a Republican Government in China.
Pending the erection of sufficient dwellings for the accommodation of so large an increase in our normal population, the existing dwellings became greatly overcrowded, but any very strict enforcement of the overcrowding laws was deemed impossible, while the penalty which had to be paid for this abnormal state of affairs—amounting practically to the conversion of Hong Kong into a huge refugee camp—was a severe outbreak of plague, no less than 1,847 cases being recorded. These cases were generally distributed throughout the City, except in the European business quarter (where only a few cases occurred), and throughout Kowloon, and the most probable determining cause of the epidemic was a considerable augmentation of the rat population consequent on the general overcrowding of the native dwellings. The overcrowding naturally led to a marked increase in the amount of waste food, both in the houses and in the yards and lanes adjacent thereto, and although efforts were made to deal with this excess by improved scavenging, yet it is obvious that where houses are overcrowded with human beings and their belongings, the cleanliness of the premises must fall below the average and refuse of all sorts will lie concealed among the lumber.
The rat population depends almost entirely upon the available food supply, and this large increase in the amount of food refuse would promptly lead to a corresponding increase in the number of susceptible rats by more frequent breeding and larger litters. Plague is endemic among the rats of Hong Kong and the infection is known to be carried forward from season to season by the Mus decumanus or drain rat, among which species plague-infected animals are found throughout the year. During the human plague season—February to July—the infection spreads to the house rat (Mus rattus) and although cases of human plague do certainly occur when only infected drain rats are being discovered, the infection being acquired in warehouses, basements, workshops, and outhouses generally, into which these rats are driven by the rain storms flooding their underground haunts, yet the maximum incidence of human infection corresponds exactly with the maximum incidence of the rattus infection, and the main efforts of the Sanitary Department are therefore directed to the exclusion of rats from human dwellings, and the limitation of the food supply of the rat population. The latter is secured by a daily collection of garbage from all dwellings, and by the efficient scavenging of lanes and alleys, while the former object is aimed at by the concreting of ground surfaces, the protecting of drain openings by...