Plague was recognized at Hong Kong in May 1894, and there can be little doubt that it was imported from Canton, where a violent outbreak-said to have caused ioo,000 deaths-was in progress a few months earlier, being part of an extensive wave of infection which is believed to have come originally out of the province of Yunnan, one of the recognized endemic centres, and to have invaded a large number of places in that part of China, including Pakhoi and other seaports.
The analysis of the Hong Kong flora indicates that about threefifths of the species are common to the Indian region, and nearly all the remainder are either Chinese or local forms. The number of species common to southern China, Japan and northern Asia is small.
During the next few years there was such a steady influx of Chinese free immigrants that in the spring of 1881 the Hawaiian government sent a despatch to the governor of Hong Kong to stop this invasion.
Simpson in his Report on the Causes of the Plague in Hong Kong (1903) reports the endemicity of the plague in that colony to be maintained by (a) infection among rats often connected with infectious material in rat runs or in houses, the virus of which has not been destroyed, (b) retention of infection in houses which are rat-ridden, and (c) infected clothing of people who have been ill or died of plague.
It did not fully gather way till 1896, when plague appeared in Bombay, but our modern knowledge of the disease dates from 1894, when it attacked Hong Kong and first presented itself to accurate observation.
Again, in April 1883, it was suddenly renewed, and within twenty days five steamers arrived from Hong Kong bringing 2253 Chinese passengers, followed the next month by 1100 more, with the news that several thousand more were ready to embark.
Meanwhile, trade steadily increased, especially with Great Britain and the British colonies of Hong Kong and Singapore.