Yersin's serum was brought here at an earlier date. In 1896, Dr. Yersin came to Hong Kong with a supply of his serum for the treatment of plague, but there was no suitable cases in the hospitals at that time, and he went on to Amoy to carry out his tests. Various modifications in prophylaxis were adopted from time to time, as a result of experience. Many of the early methods were expensive and comparatively futile in the light of later knowledge. The fumigation of houses with chlorine gas, produced by the action of dilute acid on chlorinated lime, was tried on a large scale. The difficulty of effective fumigation of Chinese houses by this means, was, however, recognised, as was also the possibility of vermin escaping destruction in the joints and crevices of the woodwork and furniture. A recommendation was later made to the Government to introduce a portable Clayton gas apparatus, which could be conveyed on a lorry to houses requiring disinfection, but the hilly nature of the City and district rendered this suggestion impracticable. The systematic disinfection of the town was attempted, but proved a very costly undertaking, and was abandoned in favour of a scheme of "general house-cleansing," in which a staff of European Sanitary Inspectors and coolies was constantly employed. Districts were treated in rotation, so that each tenement house was cleansed at least three times a year. This important measure is still being carried out with great success and with but slight modification. It has all the advantages of simplicity, efficacy and economy. Each Inspector is allotted a certain number of floors daily; the occupants turn out their household possessions, the floors and cubicles are washed out, and the bed-boards are cleansed in portable iron tanks. An inspection is made for minor structural illegalities, rat-runs and similar holes are filled in with cement at once, and all rubbish is carted away. When first instituted soft-soap and hot water were used, later a solution of carbolic acid, and now an insecticidal mixture, one per cent. kerosine emulsion is employed. Defects in premises, or breaches of regulations or bye-laws, are recorded for the service of legal notices on owner or tenant for their remedy. As soon as the importance of rats in the etiology of plague became appreciated, comprehensive measures were put into force for the abolition of hollow walls, ceilings and stair-linings. Concrete ground-surfaces, and efficient iron gratings guarding openings into houses were required; lath and plaster walls were prohibited. Nightly collections of household rubbish and garbage were instituted, and attention was paid to proper drainage. Rats were caught in large numbers, and subjected to routine macroscopic and microscopic examination. It had been a matter of observation for a long while that the mortality from plague amongst the rat-catchers was exceptionally high. A reward of two cents., later increased to five cents, per rat was given; but this had to be stopped when it was found that the Chinese were importing rats from Canton for the sake of the bonus. The laying down of a Rat Virus (Danysz), for the purpose of spreading fatal disease amongst rats, was advised, but the results were disappointing, and did not justify its general use. Wholesale rat-trapping and poisoning was not a great success, and met with a good deal of passive resistance on the part of the Chinese. The rattraps distributed in the Chinese houses, were usually found, on inspection, to have the springs of the traps released. The net result was that few rats were caught by this means. Another unsatisfactory aspect was that the rat-catching coolies were often known to threaten to report plague infected rats as coming from a certain house, if " squeeze" were not paid them. Householders were often willing to pay this form of blackmail, rather than submit to the inconvenience of disinfection, the uprooting of floor-boards, removal of ceilings, and similar measures which were enforced by the authorities in the case of premises in which infected rats were reported to have been found. On the whole it was considered a better policy to reduce the accessibility of rats to dwellings, workshops and warehouses; and, as far as possible, make such premises unattractive to them. Apparently no special protective measures, such as have been employed in India, for food and grain stores and godowns, were devised or enforced locally. General rat poisoning takes place throughout the Colony twice a year, by means of pellets of barium carbonate and molasses; about 350,000 of these pellets, together with instructions in English and Chinese, are distributed to householders on each occasion. Rat-boards coated with a mucilaginous mixture are also supplied on demand by the Sanitary Department. The present system of "rat-bins" has encouraged the destruction of rats, and has eliminated some of the disadvantages which have been mentioned. Small iron bins containing kerosine emulsion are bolted on to lampposts and other prominent places, and an inscription in Chinese characters requests the public to deposit any dead rats therein. These bins are emptied twice daily; the rats, which are labelled with the number of the bin in which they have been found, are sent to the Mortuary for examination by the Government Bacteriologist. All rats are examined macroscopically for signs of plague infection, and blood-smears and smears from the splenic pulp of ten per cent. of the rats, are examined microscopically for the Bacillus pestis at the Bacteriological Institute. The Mus rattus and the Mus decumanus are both common in the Colony; they occur roughly in the proportion of two of the former to three of the latter ; both are liable to infection. Seven to eight hundred of these rat-bins are in use throughout Victoria and Kowloon. Two or three thousand rats, probably only a small proportion of the rat population, are collected weekly in this manner, and examined for evidence of plague. An infected animal cannot always be traced to the actual house wherein it died, but a valuable indication is obtained as to the district in which plague may be expected to occur. Houses in the close vicinity are subjected to individual inspection, the cleansing gangs may be diverted to the suspected district, and other suitable preventive measures speedily put into force. Certain of the local anti-plague measures, with slight modifications, have been employed in the Philippine Islands for some years with marked success. Though there is still a great deal to be done before Hong Kong may be regarded as a health resort, nevertheless, the result of the efforts, during the past thirty years, of the Medical and Sanitary Departments, in the case of this one disease are very striking. Other natural causes, well-known in epidemiology, have doubtless contributed to this end, yet Canton, South China and the Straits Settlements had many cases of plague last year. It is noteworthy that amongst our closely-herded population, approaching a million, the incidence of plague has been gradually reduced, until at the present day we can claim that there has been no notification of either rat or human plague in the colony of Hong Kong from September, 1923, until the present date. REFERENCES (in order of publication) Published ... ... 2. 1. The Epidemic of Bubonic Plague in 1894. Medical Report by 1895 1896 1897 3. Prevalence of Bubonic Plague in the Colony of Hong Kong during the 5. ... ... ... ... ... 1897 1898 7. A Report on the Epidemic of Bubonic Plague in Hong Kong in the 1899 1900 ... 8. Report of the M. O. H. on the Epidemic of Bubonic Fever (Plague) during the half-year ending 30th June, 1901 9. Report of the Government Bacteriologist for the year 1902... 1901 1903 ... 10. Bubonic Plague in Hong Kong. Memorandum by His Excellency ... 1903 the first seven months of the year 1903 1903 12. 13. Report of the Acting M. O. H. on the Epidemic of Plague during Report on the Treatment of Plague Cases in Kennedy Town Hospital. By Dr. J. C. Thompson 1903 ... 1904 1904 ... 1904 1905 14. Report of the Govt. Bacteriologist for the year 1903 ... ... ... 17. Report on Insanitary Property Resumptions in the years 1894-1905. 18. Thesis for M. D. degree. University of Aberdeen, April, 1906. By Dr. W. W. Pearse. 1905 ... ... ... 19. Reports on the Health and Sanitary Condition of the Colony of 21. Correspondence Relating to Plague Epidemics in Hong Kong 1906 1906 Memorandum regarding The Utilisation of Sea Water as the Transporting Medium in a Sewerage Installation, by A. GORDON GUTTERIDGE, M.Sc., B.C.E., M.R.San.I., Director, Division of Sanitary Engineering, Commonwealth Department of Health. THE HE problem of supplying that additional quantity of water demanded by a satisfactory system of sewerage is one that has often confronted the authorities of those seaside communities which place full reliance for their domestic water supply on that portion of the rainfall which can conveniently be collected on the house roofs and stored in special tanks. In general, the quantity thus stored is little more than sufficient to satisfy the barest domestic needs and is totally inadequate to supply that further quantity required for the flushing of closets. This deficiency becomes still more serious in the case of those communities which have a large transient population during the summer months only. It has often been suggested that those salt or brackish waters so readily obtainable in unlimited quantities in the near vicinity of these communities, could be advantageously utilised as the flushing and transporting medium throughout the sewerage system, although uncertainty as to the effect that the salts included in these waters would have on the sewage matter and on the operation of the treatment works, has so far hindered the widespread adoption of this suggestion. This whole problem of the utilisation of sea-water as a transporting medium falls naturally into four distinct divisions which lend themselves to individual discussion: (1) Action of the sea-water on reticulation pipes, fittings, etc. (2) Transporting power of sea-water. (3) Action of the sea-water on the sewage solids. (4) Action of the sea-water during the process of Action of the Sea-Water on Pipes, Fittings, etc. sewage treatment. By the very nature of the salts contained in sea water it may be expected that the corrosive action on the metal reticulation pipes, etc., will be greatly increased over that occurring when fresh water only is conveyed. This corrosion will be particularly active during the earlier days of flow, but will decrease progressively as the interior of the pipes become covered with a protective coating. The life of such a pipe should not be so short that the continual replacements will throw a heavy burden on the cost of upkeep of the system. Where concrete pipes can be substituted this upkeep cost will become negligable. The most serious corrosive action will occur naturally in those metal fixtures |