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(c) Preventive Measures Against Helminthic Diseases.
1. There was no routine campaign. Whatever be the percentage of the population which carry ankylostomes very few cases of ankylostome anaemia come under the notice of the Hospital Authorities.
GENERAL MEASURES OF SANITATION.
1. Sewage Disposal. The collection and disposal of night soil in the Colony is carried out, partly by the bucket system, partly by water carriage.
2. Regarding the bucket system—arrangements are made with a contractor for the removal and disposal of excrement under conditions laid down by the Sanitary Board. Human night soil is a valuable commodity in China where it is used as a fertiliser for the fields, and there is no difficulty in securing contractors who will pay a considerable sum for the sole right of removal. Under a Contract made in January 1928, the Contractor pays $12,220 per annum to revenue for the Contracts for Victoria and Kowloon. Revenue from this source is gradually diminishing owing to the substitution of water closets for pail closets.
The excrement is removed by night from the latrines to a special fleet of junks which convey it up river to China where it is utilised as manure for the mulberry trees on which the silk worms feed.
3. Owing to the limitations of the water supply on the Island and the need for economy in the matter of consumption, it is necessary to restrict the number of water closets served by the public mains. Where a sufficiency of water can be obtained from other sources such as wells or nullahs, water closets are allowed. With regard to effluents, some enter the public sewers direct, others pass to biological tank systems to be treated before final discharge.
1. Scavenging—Refuse Disposal.—Scavenging, which used to be done by contract, is now carried out departmentally. There are 15 refuse lorries in use, 11 for Hong Kong and 4 for Kowloon. Two hundred and fifty-four tons of refuse were collected daily and removed to the various refuse depots. The bulk of the refuse is ultimately taken away by barges and dumped in the sea.
1. Drainage—(Subsoil and Surface).—Drainage, both sub- and surface, is controlled by the Public Works Department.